Pay-as-you-go is more risky and more costly overall but it's not an unworkable system.
Since you clarified that you mean one specific state has this system, then I'd say the rest of your post is bogus too. Current taxpayers didn't agree to build old bridges or whatever either. Few people living agreed to build out the state highway system. Yet taxes today pay for their maintenance and upkeep and it's not some great moral problem.
But it kind of is a great moral problem: A whole lot of infrastructure in the US is way overbuilt, with maintenance sent forward decades. The cost of the infrastructure isn't really handled by the people that built it, or those that use it today: It's left as a giant ball of debt to children and grandchildren.
A major reason for problems with old suburbs is that, unless they massively appreciated in value, and accept very large taxes, the per-house costs of rebuilds and maintenance isn't handled by the people that live in said suburb, but kicked outward. There's all kinds of very bad incentives, caused by how we have this kind of infrastructure. It's all over midwestern cities, and the outer suburbs that are getting built are doing the very same thing.
How do you know? Perhaps that person built or improved something very important to your life. Even if they stamped papers at the DMV for 40 years, someone needed to do that work if we're to have a functioning society.
And don't wave that away saying that worker could now be replaced by a kiosk and AI, or a contractor in India. Someone needed to do that work, manually and in-person in the 80s and 90s when that wasn't an option. If you want to slim down the civil service today, that doesn't erase the work done by those workers in the past.
Finally, remember that you don't personally benefit from every tax dollar, but as long as many (or sometimes even a few) do, then that dollar wasn't wasted on those grounds alone.
I think these are all reasonable arguments. It’s just hard for me to take them seriously with how corrupt our government is. Yes these are all factors, but the main thing is just that politicians 60 years ago decided to give themselves bribes instead of funding the pension and now I’m paying for it.
Not all infrastructure benefits everyone. No doubt some of the taxes you pay today cover the costs of maintaining boondoggle projects or wastes of money. And the pension might not directly benefit you today, but let's say those pension benefits go to a woman who used to maintain the bridge. Now today the bridge is in better shape than it otherwise would have been if they'd been done by some high-turnover, low quality employee.
Since you clarified that you mean one specific state has this system, then I'd say the rest of your post is bogus too. Current taxpayers didn't agree to build old bridges or whatever either. Few people living agreed to build out the state highway system. Yet taxes today pay for their maintenance and upkeep and it's not some great moral problem.