Yeah. I was pretty convinced she had cancer before I even took her to her primary vet earlier this week since she'd had muscle loss, and was already trying to imagine what I'd do when we paid an unbelievable sum to get to that diagnosis only to be faced with the prospect of even more expensive surgery or chemotherapy for a chance she might live a little longer.
Your experience isn't far off from from what happened to her brother a couple of years ago. His case was absolutely tragic. His initial presentation was just not wanting to eat, and his initial diagnosis was an ear infection. Antibiotics helped but he never recovered his appetite. We ended up taking him to the specialist emergency room for dehydration, and that led to a spiraling chain of expensive tests and procedures because they thought he had cancer. Ultimately they determined he just had fluid in his middle ear and needed for it to be drained. The specialist couldn't do it for like 10 days, during which time he declined to the point of no return. I finally called my primary vet only to find out they could have done the same procedure from day one. They tried it, and it helped. He recovered his appetite that night, but the damage was done. Kidney failure led to a fatal blood clot on the second day after and we had to put him down.
It was a horrendous and traumatizing experience of watching a cat slowly die over the course of 3 weeks while trying to give him medicine he didn't want. We ended up spending more trying to save him than I spent on my last car.
And for nothing.
I don't really blame the vet for the cost, but it was a very educational experience in more than one way. First, I learned to ask more questions and to try to work with my primary vet more. Second, I learned that sometimes you just have to let them go.