As for this being rich people getting richer, I'm not their accountant, but I think it'd be an awfully safe bet that they make the majority of their income from their actual careers as voice actors and directors. Critical Role has increased their popularity and visibility, and they are making enough to hire a handful of staff (looks like 10ish, dunno how many are full or part-time) and rent a warehouse, but being the voices in some of the most popular video games and many cartoons is likely a far larger portion of their income. If nothing else, I'm pretty sure Ashley Johnson isn't fly back and forth across the country and missing half the games to be in Blindspot because that's more fun than supposedly getting rich playing D&D with her friends.
Also, if anyone is excited about the profit potential of this Kickstater it's Titmouse, the animation company. The CR crew have been clear all through the Kickstarter that as much of the funds as possible are going directly to animation. Heck, the CR team are actually putting their own money into this which is why it was originally capped at 4 episodes because they couldn't justify/afford to collectively put in anymore. (I think this was mentioned on Talks Machina, but it might have been in the Q&A. Plus it makes the original goals make more sense, since they said each minute of TV-quality animation is $30-50,000, but their original KS goals only accounted for $25,000 per minute.)
So, no, they are certainly not getting rich off of this Kickstarter. In fact, they are spending anywhere between $500K-$2M of their business's - and maybe even some of their personal - money as well. (The range depends on whether the final costs are closer to the $30K or $50K per minute.) Unless they are lying, the KS clearly states that "operational costs" are <1%, and that's likely for the staff member they have handling everything involved with the KS (they mentioned her name, but I forget who it was).