I don't think this is just a nuclear problem. This is a civil engineering problem more broadly. IMO, the exact same forces which make nuclear impractical now are also responsible for the horrific budget explosions and overruns in big projects all over the US.
I have noticed that there is something like "regulatory capture" in the construction industry now, but not by the same methods as most other industries. With giant, multi-national corps handling most large construction projects now, the QA/QC engineers are either incorporated directly into the company and thus never stop terrible practices, or they are there as a sub-contractor to the prime contractor and thus will be replaced for 'other reasons' if they give push back. It's now a push to the bottom for quality and the industry is going to hell quickly as the Engineers who value quality and ethics are slowly pushed out or forced to submit. If a small engineering company tries to stand up to one of these behemoth construction corps, the smaller company will either be blackballed behind the scenes (if they're lucky enough to be temporarily successful in their challenge) or the behemoth will lean on the nearest municipal gov't and say something along the lines of "We would love to finish this critical project, but we're being held up by this silly requirement and this silly engineer. (implied: Since we're on a Cost Plus contract) It's costing you X,XXX,XXX per day while we're held up. You should probably give us a way to get past this issue."
It would be funny if it weren't so sad. Civil Engineers are getting crapped on by both sides for increasing costs. They are blamed for holding things up with quality checks and at the same time for not doing enough to stop the terrible practices that result in long-term failures which end up increasing costs further. Payouts are going down for QA/QC companies and the pressure is constantly increasing to let things slide. The differences between a well-regulated project and an 'unregulated' (for all intents and purposes) project are shocking - you can feel (and see) an attitude of IDGAF from everyone on projects where it is known that the regulations don't REALLY apply.
My guess is that by the time we have regained any such capacity, renewable and storage will be cheaper than the thermodynamic process of harvesting heat and turning it into electricity; a process that has been hyper optimized for a century without much progress, and which has hit the wall of thermodynamics in efficiency. The only way to improve its cost would be far cheaper materials, a revolution which might happen with 3D printing, but which is super speculative today.
Efficient homes, renewables, ubiquitous internet connectivity, and electric vehicles are going to be your targets as people spend more time at their homes and the trips they make can be electrified.
(the above comment is predicated on developing countries aging rapidly causing workers to leave the workforce, the quick uptake of remote work due to the pandemic forcing employers to learn how to support it, and data showing people fleeing cities for the suburbs and lower density living arrangements in general)
Why can't we use an affordable safe/competent reactor design from 30-40 years ago, and stamp that out at scale, rather than building a "new" model that results in failure?
However, they're also the main type of reactor that actually got built and works.
You can't examine the differences in project management and execution while the project is still on paper. You have to commit years and billions of dollars to determine if a project is going to adhere to the original plan or blow out on time and/or money.
Right now South Korea has the best track record of rapidly, affordably building reactors. Some American nuclear proponents think that we should just have South Koreans build Korean reactor designs here, to bypass the apparently irremediable problems in the domestic nuclear industry.
But even the smooth progress of South Korean reactor builders is not assured when they are building outside of Korea.
The Barakah Nuclear Power Plant, built by Koreans with Korean reactors, just powered up its first reactor days ago.
https://en.wikipedia.org/wiki/Barakah_nuclear_power_plant
The timeline from construction start to operation was originally 5 years. It has actually taken 8 years. It's 60% over the time originally scheduled, even though it is using a standard reactor design built by the most competent reactor builders currently available.
(In addition to what pjc50 said.)
edit: Never mind. The system inherits elements from a design used in the Palo Verde NPP near Phoenix, AZ
Probably know how to handle the heat...
Logistics isn't easy. Dirt isn't simple stuff, neither is waterway management, nor concrete. Hauling a giant steel pressure vessel from its point of manufacture to point of installation isn't easy, nor is its installation. Just because it looks simple to a layman doesn't make it simple.