The main issue is that the first thing you have to do is secure your financing then you're paying interest on your loans over the near decade it takes for the regulatory approval apparatus to do its thing. If this allows you to get approval for a one reactor site with the right to expand to 24 more reactors of a given design without re-approval it might be very significant.
The other issue is that each nuclear reactor site is effectively unique. So there's whole piles of paperwork that need to be checked and re-checked to ensure that all procedures and everything is correct and up-to-date.
With small modular reactors and similar, all the critical bits are made on a production line, and completely standardized. This will drastically reduced the paperwork and training needed to operate it safely.
