Its been said UFC fighters can receive free training and free meals at the UFC Performance Institute in Las Vegas. In addition they're supposed to receive royalties for all of their signature items in the UFC store that are sold. Those are probably the two biggest changes in recent times that fly beneath the radar.
I would seriously be curious to know how much bellator MMA fighters profit from dude wipes sponsorships. There have been claims of 5 or 6 figure payouts but somehow I don't think dude wipes has the cash to throw six figures at MMA fighters in bellator.
Interestingly enough, Rory MacDonald was publicized as receiving a 6 figure sponsorship payout from dashcoin when he competed at bellator. That claim might have been legit. In that there could be some truth to claims of large sponsorship payouts outside the UFC if only on a limited basis.
Yeah, I'm sure there are some deals where a fighter does not have to pay for food and board, however, most of those deals are made with not yet established fighters that live train, and eat at the facility. Also, yes, the UFC training facility does offer that, but not everyone is willing to relocate to Las Vegas.
As for sponsorships, yeah, there was much more money to be made before the rebook deal, and Rory was one of the more outspoken fighters that lost money when rebook set in.