It changes nothing, what you describe has always been the case even before AI. There are things people can build in a weekend that take weeks or even months at a larger company. Large companies have a way of slowing everything down, for reasons that have nothing to do with coding.
Correct, but the amount of people who can do it has drastically increased, and the amount of time it takes for most people to build these things has drastically decreased.
It has not drastically increased. One could even argue it has decreased. Ultimately, the productivity gains will perish to bureaucracy.