As for fun, they're not having fun since they're doing it wrong with the result of trying (very successfully!) to eliminate the RTwP genre altogether. It's imperative that someone break through to them so they can stop making themselves miserable trying to play tennis with fine violins and bashing them into the ground in misplaced frustration.
I don't disagree with anything else you've said, nor with any of the other arguments, but this one seems shaky. I remember RTwP coming into play because "computers can keep up with us now, lol, no need to be turn-based anymore". ~20 years later: "lol, computers are pretty fucking fast now, we can't keep up with them, let's slow things down to turn-based".
Is it survival of the fittest, or just a preference?
Trick question. It doesn't matter as long as you have fun. Both the options panel and the light switch for TB mode are optional, not mandatory.
In theory, you should be able to beat the game never having to pause the game.