That is exactly my point. I get my sh!t together on my own; the band has no time to waste teaching me fundamentals. Conversely, I have no time to waste while you work on your fundamentals. Rehearsal is for working on making the piece sound good with the whole ensemble.
I have done plenty of gigs, including originals, where all I get is a song list with keys and a recording, and playing the gigs goes just fine. This assumes musicians who have their fundamentals down. If the band can't get together the fundamentals of playing time on a tune at rehearsal, someone's not up to snuff, and that's not a gig I would hang around for.
I just went through something similar with one of the originals projects I'm in. The BL/guitarist/singer's time needs work, and we started rehearsing with a metronome. The quality of the performances went directly into the crapper, since the band members unfamiliar with click tracks were playing to stay with the metronome on every beat. Maybe that's a subconscious thing or a throwback to lessons. Once we got back to actually performing the tunes at rehearsal (and maybe checking tempo before and after) things started to sound decent again, and we could easily tell who was doing their homework and who wasn't.