Blue states have all of the money. There is no reason for them to complain so much about the Senate. If they want a vast socialist welfare state with state of the art transit, they should be able to pay for it themselves.
Michael Dell wrote in his memoir, that each time Dell Computer doubled in size, he had to completely redefine their processes. Well, the USA has grown a lot. Trying to fit 50-100 year old processes into the modern economy is bound to fail, for lack of scale and imagination.
A public transit system is honestly cheap at the price. Kind of a enlightened-self-interest thing. It lowers the cost of working, lets people make more choices about where to live, and generally makes markets more efficient.
Republicans being for states rights hasn't been true for my entire lifetime (30+ years).
There are a couple of areas where Republicans support federal preemption, such as telecommunications (which falls squarely under even a narrow definition of the commerce clause, as “channels of interstate commerce”). But for the most part they fight federal encroachment in environmental laws (regulating infra-state bodies of water), health spending, etc.
When have Republicans had the federal government intervene to stop a domestic transit or health program that wasn’t reliant on federal dollars?
Is California rich enough to pay for its infrastructure projects by itself, or does it need money from other states to do it? If @seattle_spring is right and California doesn't need the money, then the Senate isn't holding anything up. California can proceed unilaterally. Maybe they can even vote for Republicans at the federal level, who won't make them continue to "subsidize rural living" in other states.
But if you're correct that California "need[s] federal funds to keep up with these expenses" then why shouldn't the rural states oppose it when it won't benefit them?
The reality is two-fold.
1) People in dense urban states aren't actually willing to spend this money, they just want to use these issues to get votes for Democrats. That's why they never actually build these things when they have to do it with their own money only.
2) Dense urban states want access to the Federal government's money printing machine. States cannot run structural deficits. But the rural urban states will be on the hook for that debt too.