Well, you do have to move a lot of earth and pour A LOT of concrete :) Many steps have to be x-rayed, and many other tests done before other steps can be started. Every weld is checked and, all internal and external concrete is cured, treated, and verified. If anything is wrong, it has to be fixed in place (if possible) or removed and redone. It's a slow process and should be for many steps.

One of the big issues that have occurred (in the US especially) is, that for 20+ years there were no new plants built. This caused a large void in the talent pool, inside and outside the industry. That fact, along with others has caused many problems with some projects of recent years in the US.