I hear ya.
The one and only time I got to play at the Hole in the Wall in Austin, our regular drummer couldn't make it, so he hooked us up with someone who "was great!!" The guy was like, "Nah, we don't need a rehearsal, i listened to your songs and I got it."
Nope, he didn't "got it". The worst part was after our set, the manager came up to me and one of the guitar players and said something like, "I was hoping to get you guys into a residency with us, but I don't know...."
This explains why some hesitate or outright refuse to use subs. However I have performed with subs who have come in and performed better than the members they were replacing, with no advance rehearsal. It was a genuine epiphany. Sure, you have to know who these top players are, and also be willing to pay them. For my local bar gigs, that would be $150 if I'm lucky. One top sub drummer I hired accepted the $150 equal cut, but he performed so well I gave him a $50 tip out of my cut (my ungrateful bandmates were unwilling to chip in

).
Side note: sometimes I purposely double-book backup options 1 and 2 if I’m uncertain who’s going to work out. If both are ready, I pay one of them their gig fee not to play with us. I hate to cancel, but people know if I book them they’re going to get paid, regardless.
Amen. I'm semi-pro, but my brother is a pro musician and has taught me a lot. For example he explained that if he is booked for a sub gig but then gets cancelled on somewhat short notice, he still expects to get paid. Reason being, a contract is a contract: he blocked out that date on his calendar. and likely turned down other work for it that can't be rebooked on short notice.
I should emphasize to all who don't know: if you line up a sub because a regular member is unavailable, but your regular guy becomes available shortly before the gig, the sub drummer should still get paid.
Commitment works both ways! Would you like it if the sub drummer said on short notice "sorry guys, but my regular band got a gig that night and they get priority, so I'm no longer available to work with you".
Anecdote: I was subbing with a band who was in between bass players. They gave me eight gigs over the course of spring and summer. During gig five, the BL said "hey, we've found our guy, he'll be ready to go next gig. So we won't need you any more, but thanks a million for helping us out". Now, I'm no top hired gun, I'm just a semi-pro bar band guy, so I wasn't about to demand full pay for those three gigs. However I did gently explain about commitment being a two way street, and that I did turn down other gigs to keep my commitments with them. So they offered double pay for that last gig, and I accepted. They weren't thrilled, but at least they realized that some compensation was proper.