I think that depends on each user personal experience,me despite not winning from a long time I have won before several times x2000-x3000 in Play n Go provider although nowadays this provider is offering casinos changeable RTP which I believe has made me not winning anything more than x400 in my best win from the latest session and latest free spins from Green Knight slot.

I think there are people who have hit it big in No Limit City which is notorious for their huge max wins that other providers lack most of the time but as you said it is extremely difficult to get such high multipliers without playing for a long time in such slots.