RPGs are not much more complicated compared to some other games. The difference is that the other games actually bother to teach you the rules, and don't overwhelm you with important choices when you're just starting the game.
Take POE for example. You need to select your character class (before knowing what classes do), your race (before knowing what races do), distribute a bunch of stats (before knowing how the combat system looks like), chose some spells (without actually experiencing how spell casting works) and some bonus feat (not sure on that one). Now compare it do Dark Souls, which is massively popular among normies everywhere. You start the game, select a preset that looks somewhat appealing to you and you're off. In you don't anything about RPGs creating a Wizard in POE is pretty daunting, in DS you just select the wizard guy. You can make all the important decisions after you know how to play the game.
Dark Souls isn't even considered an RPG by many here though. Most of the games that let you just jump in either aren't RPGs, or are on the very edge(e.g., twitcher 3)
I haven't played it for a while, but I remember DOS2 character creation being very quick — could partially explain its wide appeal.
Another thought: are classless systems inherently easier for new players to get into? Class-based systems frontload heavy decisions on the player, whereas classless ones generally have you slowly moving towards the character you want and picking defining skills/abilities/whatever much later in the game when you have a better understanding.
I think a lot of the recent RPG 'hits' have been classless, might just be a coincidence however