Is 10 young? Yes. Are there plenty of Fanconi dogs living much older and in good shape? Yes. But I do wonder if other things are also going on with her, medically. And it does not sound like AT ALL that you have missed enough pilling to be a reason for the disease progressing faster. Sometimes no matter what you do, it just does.
Can she live on pasta? Yeah, if you ground chicken with it so she's getting protein.
I am sorry the Wimauma dogs have such high rate of Fanconi, but I hope that the research Pam is undertaking to see if supplementing low levels from Dx instead of blood gas indications may help stave off symptoms ever beginning. And I hope that we get such high rates of testing and responsible breeding that Fanconi becomes totally rare ever. But for now, people like you end up suffering, I believe, more even than the dogs you love because of it.
I am going to be flamed, but I don't much care.
I don't know if she would be her old self if you got her routine 100 percent. I don't know if things would be much easier if you got her on cyproheptadine or another appetite enhancing drug so she was HUNGRY and would eat easier, including pilling.
I do know that I believe you have the absolute right to say enough and let her go, even if the above were true. You sound so sad and exhausted. You have given her your all for so long and if you have reached a point where you just can't keep doing it, realize inside that you gave her a better life than 99.99999 percent of companion animals on EARTH get for even a year, much less 10. If your gut says time, it is time. I wish I could send you the strength to not second-guess or be so sad, but all I can do is say thank you for being the kind of owner I wish all dogs could have.