It's harder to find quality people who are willing to relocate their family every time a job is finished.

A large portion of the workforce which recently completed Vogtle units 3 and 4 temporarily relocated to the site from around the country. Many people lived at RV camps opportunistically setup by farmers or others with large empty lots. Especially if you had family, living out of an RV was a good way to minimize expenses and maximize how often you could afford to travel back home.

At big jobs like these, especially outside a handful of major metro areas, there will never be enough local labor. Even for "unskilled" positions, you don't want too many unproven or inexperienced people as they're likely to cause trouble, such as hurting themselves or others, or not consistently showing up on time--schedules can be both grueling and erratic, and many people can't hack it.

Tesla could never reach full capacity at GF1 because they couldn’t find enough people willing to move to Sparks, NV. Also why they picked Austin for that GF.

The nomad tradespeople you mention exist, but they are rare, and most likely dwindling as they get old and die and no one replaces them (a problem all trades currently).

Yeah, I was thinking if you can afford to pay people to go live on an oil rig you could pay people to live in a small town in a rural area.

To be fair, in a lot of cases you'd probably build multiple units on the same site which would get you some learning effects. But compared to wind, solar, and batteries...

Do you know many pipe fitters?

I believe that is how KEPCO operates on the reactors they build outside of Korea.

it's not only the workforce, it is also the difference in bureaucracy and regulations between each state which limits knowledge transfer.