I feel like there's a fundamental breakdown somewhere along the way here for some folks in this discussion.
'Incentives for RP' does not mean incentives for just any ol' RP. Some games used them that way, but that was because they were copying the games that came before them, not because they understood it.
Votes -- and other incentives -- have always been about rewarding the specific behavior you want to see.
Some games made them worth more for new people, some games made it so familiar people couldn't vote you once in a while, some games pooled them all together and split the rewards amongst the playerbase, some games capped how much a given person could spend, some games -- it goes on, and on, and on. But it's never been just 'we have to bribe people to play at all'.
So the question isn't actually 'how do I reward people for roleplaying when I do not want to use XP?' because you're right, it's stupid, and nobody's actually doing that. The question ACTUALLY is:
'how do I reward people for <a particular behavior I want to see, such as helping new people> without using xp?'
That's an easier question to answer, because it's specific, and it shows us all what we're actually trying to accomplish.