The number of people playing a slot doesn’t change the RTP itself, but it does speed up how quickly the RTP is realized. For example, a 98% RTP means the slot is programmed to return 98% of total bets over, say, a million spins. More players = more spins per minute = faster approach to that average.
Now, factor in the massive max wins that blow way past 98%. Ofcourse those are only hit by a handfull of players. Add the other mid-high payouts that also exceed the average. The math balances out by giving most players really bad RTPs, sometimes as low as near-zero, to bring the average back down. So while some win big, the vast majority are essentially getting rinsed.
That’s why you hear Eddie on stream saying, “Whoa, that’s such a volatile slot, it could pay nothing.” He’s not kidding.
So now what is more probable? Being among a handlful of players that will get a psoitive return, or being in the vast majority getting rinsed?