This is also true in my case. For nearly 20 years my primary RPG was Rolemaster. I also played various games on the side: AD&D, and various BRP variants like Stormbringer/Elric, CoC and RQ. I noticed the arrival of 3E, and played a small amout of it, but it didn't seem super-exciting to me.
The announcement of 4e came at the same time as a second long-running RM campaign was coming to its conclusion, and also as our group was undergoing reconfiguration due to some members moving to the UK, resulting in merging two groups (with some overlap in membership, and the other of which had been playing 3E) into one.
It was obvious from the get-go that (i) 4e would have a mechanical heft comparable to RM, and (ii) it would be almost the opposite of RM in its approach to mechanics, adjudication and the relationship between these things and the fiction.
Over the past decade or thereabouts I've often posted that 4e fully delivers on the Gygaxian conception of hp and saving throws as a "fortune in the middle" mechanic that can be narrated as skill, luck, verve, and anything else that contributes to staying power.
And I've also often posted that it delivered on the promise of Moldvay Basic's foreword:
4e delivered.