I disagree, there is almost nothing incommon from 2e to 3e, 4e was less(all be it not much) of a change...
I don't want to get into the mud on this one, but your very close to wrong on this.... my group playtested 3.X and jumped from Skills and Powers (2e product I still own a copy of)
the leap of faith was much shorter... classes >>felt<< the same, the math was simple to grasp (oh roll high on all of it) and spell casters felt the same (prep-spells and cast them.. ok prep them in the morning.. cast again)
4e stepped far away from the classic D&D paradigm by giving everyone the same type of "powers" at will, once encounter, once per day... someone coming from 2e would see almost no similarity between 4e and 2e... there were even significant race differences (gnome a monster what? dragon who?)
Think if it as going from Windows 98 to Windows 7.... compared to going Windows 98 to Windows 8.....
they are both windows.. but one feels familiar but the other feels like a new OS
No, I'm not saying 4e was a bad game... although the combats did last a little too long (but that was an easy tweak..) and the skill system felt shallow... but it had a lot less in common with its predecessors then any other version of the game.
which alienated a LOT of players... I use to run many of the conventions in miami.. I saw it first hand... the younger players eate it up, but almost all the older (2e or 1e players) gave it a few weeks and said "this is not D&D" and stopped playing... way before Pathfinder made its appearance.. many of them went back to playing 3.X (someone started running all the Living City adventures all over again for gods sake)
again.. I'm NOT bashing 4e.... it not a bad game, but it was a huge leap in design that changed... for many players.. the feel of the game... and for gamers the feel of the game is almost everything
why do you think 5e feels like 1e/2e?