Yeah you can look at it two ways....the lesser teams have caught up or the better teams have fallen back......
maybe a mix of both. For me, the way the game has changed, that top teams are more structured, say like a mourinho team or conte team. They are set out, hard to break down first and foremost and build on that. That is the easiest way to play football. so the lesser teams coipy that and even with lesser or more average players, that can still reach success cause its an easy way of playing the game.
So the top teams have adapted an easy strategy - it requires high levels of concentration and discipline, im not saying its easy, im saying its easier than playing the way, say a Barcelona do. and this structure and way of playing is easier to copy for a lesser team and lesser players can do it every bit as effectively as top players, even more so as very often a lesser player is more dedicated/disciplined cause he has to be.
So the top teams aren't battering teams any more, cause it isn't in the nature of how a lot of them play. Its for this type of reason that the likes of Holland did qualify if you ask me. Lesser better organized teams could beat them cause Holland wanted to just go and play - you just cant do that.
And its also for these reasons that there aren't as many outstanding talents around anymore. You look back 10-15 years, look at the strikers that were around. brilliant ones all over the place. Apart from the three lads at barca and Ronaldo(if u consider him a striker), who is a top level striker in world football? Aguero? Griezman? Anyone else? The game is suffereing cause of how the tactics have changed.
Defensive structure, organization, discipline is the main thing now and lesser players can meet those attributes much easier than they can copy the skills of a messi or a suarez. So that for me is why the tournament wasn't great and why lesser teams are catching up or bigger teams are falling back, whatever way you want to put it.
And it may also be why the great players aren't forwards anymore, they are midfielders, even defenders, even goalkeepers maybe. Skill and technique is being coached secondary to physique and discipline. Kinda sad ina way. There'll always be the payets and the messi's and the like but its gonna get harder and harder for them to make the break through when teams are looking for Kante's and big strong powerful guys rather than the skill and technique.