In Seattle there's a company called "Sustainable Living Innovations (SLI)" that a few years ago started this modular apartment building that was supposedly going to fly right up because their modules are so efficient: https://www.king5.com/article/news/local/seattle/company-bre...

That was two years ago, and I can clearly see the building is still not done. It's gone up at a snail's pace compared to "traditional" construction nearby. Might be that the company is having financing and/or supply-chain issues.