I mean, we know we can build nuclear plants quickly because we've done it before. It is physically possible. China and Korea can still do it today.
If you just mean the bureaucracy is impossible to defeat, it would just take political will. Which we are seeing more and more of recently. The first of a kind build is always slow.
Depends on what you mean by "we". China is doing it as we speak.
Also, "it's been done before" is a much better argument than "we think we can make these massive and untested changes to our society because my studies say so" like I see constantly from solar/wind maximalists on demand response, mass v2g, hyper connected grid, underground hydrogen battery etc, etc.
If you just mean the bureaucracy is impossible to defeat, it would just take political will. Which we are seeing more and more of recently. The first of a kind build is always slow.