Statistically, if you take the top 3 teams most likely to win it all (right before the tournament starts), it's almost always going to be less than 50%. The field is more likely to win the national title than your top 3 favorites. And no, everyone does not get close. If they do, then Villanova and Virginia would have more than two Elite 8 appearances this decade.
Duke very easily could have been in the Final Four the last two years (Grayson's shot that rolled around in the cylinder + a 1-pt loss this year). Kentucky probably could have won a title in 2010, or 2011, or 2014, or 2015. It takes a bit of luck. UNC won the title in 2017. But it's not like it was a cakewalk. They very easily could have lost to Arkansas, or Kentucky, or Oregon, or Gonzaga. It's a game of odds. If you replay the 2019 NCAA Tournament 10 times, I bet you'd have 6-7 different winners. JMO.