Why haven't we collectively emphasized the creation of new tools to reduce boilerplate and grunt work?

You dont understand how things evolve.

There have been plenty of platforms that got rid of boilerplate - e.g. ruby on rails about 20 years ago

But once they become the mainstream, people can get a competitive edge by re-adding loads of complexity and boilerplate again. E.g. complex front end frameworks like react.

If you want your startup to look good you've got to use the latest trendy front end thingummy

Also to be fair, its not just fashion. Features that would have been advanced 20 years ago become taken for granted as time goes on, hence we are always working at the current limit of complexity (and thats why we're always overrun with bugs and always coming up with new platforms to solve all the problems and get rid of all thr boilerplate so that we can invent new boilerplate)