Whether Arizona state government funds this is largely dependent on who gets elected there in 2022. The Republican Party of Arizona is currently trying to prevent people from voting because they don't think they can win honestly.
If they continue to control the state government, it is quite possible that Metro Phoenix and Metro Tucson will be willing to provide the funding themselves.
Rebuilding the Phoenix West line is, frankly, easy. Yes, it has to have the track and ties and ballast completely replaced, but the right-of-way and subroadbed is in good condition. Desert conditions preserve it pretty well. It's not like restoring the Scranton to New York City line, which has to be rebuilt below the roadbed, with bridge restorations.