A lot of NIMBY/racism/classism and modern reality of legal delays means that it can be costly.
Zoning laws is another. It's a lot of fun visiting Japan and Taiwan because you can wander around and there's a huge variation of utilization in a given block. US approach to zoning means that I rarely see similar utilization in the US.
Separate from this is politics.
I'm in the NYC metro area and we've been trying to expand access into NYC for decades.
You would think that this would be a no-brainer because it enables so much economic activity in both directions (NY/NJ). Yet, Chris Christie canceled the ARC project (which itself was years in the making) for optics at the time of the Tea Party.
NIMBY seems to have a hard time stopping data centers. Why do they have more success stopping renewables and rail?
There's an existing disused commuter rail line in NJ near the Hudson that was shut down in the 60s. It still has many of its stations and density to support rail service today but can't be reopened because of the NIMBYs. If they can't make that work, the rest of the country is mostly hopeless.