Raids should kick out pokemon
Easiest fix to the whole pokemon have to come back to get coins. When a raid STARTS, the pokemon get the boot, bringing back whatever coins they earned, whether 10 minutes, or 10 days. The gym then goes neutral after the raid. This would fix some of the issues, the fastest way possible, until a real fix can be created
Answers
I think that could actually be a "real fix", even better than a "cash out" approach where one can selectively bring home a defender, which would be a little too convenient to spoofers who would just immediately slot in their next mon. At least right after a raid there are might be some legitimate players around to fight for control of the gym - could contribute even more to the "cooperation" mode that Niantic says they want to encourage.
Also doesn't benefit them to piss off the loyal, and have them lose interest. It benefits them plenty, they already lowered the coin cap. Even if you reach the 50 coins a day, you cant buy anything with 50 coins. If you max twice, then you have a raid pass yaaayyy, if you max three days, an incubator. Lowering the max already makes people p2p, lowering the max, and giving them a small chance to reach it, and working harder to get it... no one pays and no one plays