I don't know. I'm a 3.5 Veteran, so Multiclassing is in my blood. 5E doesn't really gravitates towards this...
We must run in very different circles. At a minimum, Hexblade made multiclassing a requirement for Paladins and Melee focused Bards and I don't think I've ever seen a pure Barbarian or Fighter past level 5ish.
I'm with you there, the current game I am the DM for, which is 5e, four of the five original characters were multi-class by level 7. We lost three players and had to replace, and the two new players are just one class. In the game I am currently a player in, my character is multiclass Rogue/Bard at level four, and I know two of the other players are already considering a dip in other classes for their next level. So I think multi-classing, or not, is very much a YMMV situation.
