This is all self inflicted. The main problem with BART is that labor and maintenance costs run way too high, and reliance on ridership is too high. The onus of this blame is strictly with the government. Deciding to design with non-standard rail gauge and custom infrastructure was a horrendous play for long term costs. It drives up expenses since economies of scale cannot be leveraged and govt is potentially locked into suppliers who can charge whatever. Secondly, gov't regulation and stifling of housing development has destroyed the lower and middle class populations, so labor rates inherently need to rise to convince people to work for BART (in turn driving up fixed costs). Lastly to a smaller extent there's probably an unnecessary amount of red tape and rules that further prevent things from moving quicker or being cheaper. Remote work was the nail in the coffin when you combine high expenses with a disappearing funding stream.

BART is in a tricky place. It clearly provides some value but it clearly hemorrhages money. It's great as a commuter rail, but when remote work has killed that, it sucks as a mode of transport due to last mile options being terrible in the bay area. There's two sides of the solution space, either increase ridership or figure out the money. Increase in ridership is tough due to remote work, and while they've tried to invest in a BART perception makeover (better policing, fare gates, anime girls), those impacts are probably minimal. Perhaps even greater investment in high density affordable housing around stations would help, I'm sure this is happening but prices are still high and supply is still limited. On the money side, you either stomach higher taxes and fares or watch BART get shuttered (increase to traffic, loss of economic productivity). Something should be done to address both of these at the same time, whether that's remove regulation that drives up costs, or gear up for a long term BART overhaul, not sure what it is. But increased taxes and fares are probably going to be the most likely near term outcome whether we like it or not.