On the flip side, my mother in law had her bathroom "refinished" by this local place- 30k... "3 day job" - 3 people.
She is asian and ocd, they have redone the entire job twice now, replaced half the fixtures and vanity 3 times now and there are still things not right (to her).
First off, that dude can cry a river- no "10k" bathroom should be taking him a month even with "a labor" - no normal bathroom, even a large big house double bath... The "problems" you run into are not that difficult if its a complete rip out- generally once you get the walls and floor out, fixing the "big issues" is not overly difficult--- rotted subfloor? well, your down to it, so rip it up and tack in some plywood, oh so hard-- but "We gatta replace your sub floor" sounds expensive! vs "We nailed in some plywood" - OH MAN ALL YOUR PIPES NEED TO BE REPLACED!
Sharkbite is now certified in wall - there, all your old stuff can be stubbed into PEX or whatever you want and you do not have to bust out ye-ol solder and torch, just a hack saw and sand paper.
Back to my mother in law... they are doing this refinish stuff where they overlay this resin based acrylic sheet over old tile work for the tub, put down fake tile for the floor that is glue n lock- so its all 1 day, no grout etc. They cut out the shower, redid the pipes in pex, put up plywood, overlayed with the same acrylic stuff, tore out the vanity put a new one in, new toilet. 30k my butt... 15k would still be high imo but at least within "reason"
That bro aint doing no 10k bathrooms, and if he is- its some tiny bathroom like mine that costs like 1k in materials and 200$ in mexican tile work.