I am not an American so forgive me if this answer is not viable due to the structure of American government, but the simple solution is continuous and steady investment in public transit detached from political tampering.
Many of these failed referendums were about creating a local tax in order to provide that dependable pool of transit funding for expansion and operating costs.
A solution would be for the government to take the initiative and start seriously funding public transit, considering it a first class citizen along with the road and highway network.
The roots of the MTA were in an agency detached from political tampering. It used the lack of political influence to raze entire neighborhoods to build freeways.
The MTA was mostly created to remove this power from Robert Moses.
Many of these failed referendums were about creating a local tax in order to provide that dependable pool of transit funding for expansion and operating costs.
A solution would be for the government to take the initiative and start seriously funding public transit, considering it a first class citizen along with the road and highway network.