Food for thought. Dexterity, coordination, reaction time might not be a massive requirement in RTwP games as such, but these things are as you say a substantial part of all shooters, sports games, action RPGs, really of majority of games in general. Now the millions and millions of people playing these type of games, I'd like to think it'd be easier for them to pick up a RTwP game than a TB game, TB just feeling too slow for a decent shot in Battlefield/Apex Legends.
On the other hand.. maybe after a few hectic matches in CoD or an adrenaline fueled session of the latest DOOM, kicking back with a TB crpg is just what you need. Chill and afford yourself to take your time, for once.
What direction "mainstream gamers" lean, if picking up crpg's? I like to speculate.
