(In the following all matches that were decided by the penalty lottery are counted as ties).

 It is more difficult for the best team to win the World Cup as many believe. This is caused by the way the Cup is played. A knock-out system does not forgive a mistake in the wrong moment, a bad day, or even just bad luck. Remember Brasil 1990. Maybe they were a team about to lose only one of twenty matches, but they had this match in the first knock-out round. So they did not have anymore matches to prove how strong they were and went home as a failure.

 It is almost impossible for a team to win 7 consecutive matches. Most teams who reach the finals of such big tournaments, have to sneak through somehow at some point, or at least had a low point in the first round. The only team that could win all their matches since the second world war has been the Brasil of 1970. But since then football has changed, the matches have become closer, more and more decided by single moments. Germany 1982, 1986, and 1990, needed a won penalty shoot-out along their way to reach finals, in 1982 and 1986 they had lost first round matches to Algeria and Danmark. Italy 1982 and 1994 had struggeled in the first round and somehow got through, while the strong 1990 squadra had their problem suddenly in the semis. Belgium made the semi-finals 1986 despite winning only two matches, Sweden did not win any more 1994 (apart from the 3rd place play off). And Brasil 1994 had the necessary luck of most of the recent World Champions: with Netherlands they had only to beat one single top team to reach the finals in which they then could not defeat the Italians in 120 minutes - they needed a penalty shoot-out.
The same can be said of France 1998: only two of the superpowers crossed their way: Brasil in the final and Italy in the quarter final, again a penalty shoot-out was needed.

 Imagine your machine is runnung well right from the start. This can be a cloud to sail on but it can be a psychological problem as well. There is not much room for improvement but for doubt. Suddenly there occur problems. Many teams which played above their average potential for some matches then were bitterly punished. Think of USSR and Denmark 1986, even Spain. Romania could not keep the same level for all matches in 1994. Among teams that struggeled in the first round and then pulled together were Germany 1982, 1986, Italy 1982 and 1994, Bulgaria 1994, Argentina and England 1990, or Germany 1974. Sometimes it is very good to have a bad moment in the first round and then see yourself improving. It is only very difficult to plan such a moment. 

 Now we come to the chances for the favorites to win it. First one has to define what percentage means here. Let us create a 'best team of the world'. Let us call it Brasil. If you say this Brasil wins the next match by 85%, despite the high value, this does not mean at all that indeed Brasil will win. It only means, was the match played 100 times, our Brasil might win round about 85 times. But which match you will see, one of the 85 or one of the other 15, this value does not tell you at all. Another way to look at it: Winning 6 of 7 matches is a terrible high value. It means anyway that you do not win one of those seven matches. If you think of the World Cup, which one will it be? A first round match? A knock-out match?

Anyway this value is much to high. Brasil might win its 6 of 7 matches against minnows but think of the matches against Argentina, France & co. In those matches the odds should be almost down to 50:50. The way teams have to go in their World Cup adventures is hard to predict. It has showed in the past that not all favorites who make it through to the second round win their groups, usually some of them, qualify as runners-up. This could mean, and now we turn to the World Cup 2002, that instead of a considered relatively easy 2nd round match match against Senegal, Uruguay, or Danmark, the World Cup co-favorites Argentina could face World Champions France.
 It is possible that France has to beat England, Brazil, and Argentina to reach a final while someone else might to have to put off 'only' South Africa, Mexico, and Spain.

 Let us pick France as our superteam and let us consider an average value of 75% (made of a 90 % against Nigeria and a 60 % against Argentina), what is very, very high, for France to advance in any play-off match. As shown before, this value means, if looked at from the other side, France would lose one of four matches (or at least draw and go out on penalties). So it is obvious, France, as any other team, to win the World Cup have to be above-average lucky: They have to win all four knock-out matches in a row! This requirement of luck is caused by the number of four play-off rounds and the high number of participating teams, this is not because France are not strong enough. 

Now you can calculate the probability of France winning: It is 75% of 75% of 75% of 75%. Or easier: 0,75*0,75*0,75*0,75=0,316.
Only in 31,6% of the cases this superteam team wins the World Cup. This is less than every third World Cup. And this value even neglects the slim possibility of an early first round failure and does not take the qualification into account as well.

That even this value is too high, you can easily imagine, if you consider the following: The 100% have to be distributed on all the 32 participating teams. OK, you might be able to neglect some teams now, but if France has 30%, there are only 70% left for Argentina, Italy, Cameroon, England, Germany, Spain, Japan, and Portugal (plus all the rest). This means less than 10% in average for each of those giants. Now you might start to develop a feeling for how much luck is involved in winning such a tournament.

If you played out the championship on a league basis, this all would become different. But the effect we can watch here in the play-off system is caused by the fact that a team that has lost, cannot play on anymore to recorrect their result. In a league you can lose the first match and win the rest, in knock-out football you are out. Also teams might face a schedule of different difficulty. 
Remember that Brasil has had brilliant teams at each World Cup since 1982 but anyway not reached the semi-finals between 1982 and 1990!

(About all single evaluations you could argue, but you should try to see there is a general tendency that is not much affected by changing the values by some percent).

 Anyway, single results of such stochastic processes are not predictable and somebody has to win. 
Why not France?

That this is not a fantasy of The Shot That Passed Right Throught The Net you can see when you analyse the odds of the bookmakers. For those real experts (they risk their existence if they evaluate wrong) the hottest favorites are rated only at about 20 % or lower to lift the Cup.