[ModernMech]

I like your idea a lot, but I don't think it could replace the Ph.D. proper. You really do need all that time on one project to make a dent in the state of the art sometimes. One year I spent an entire summer generating data for a single figure in my dissertation. That's part of the reason why it took me 8 years to graduate.

[barry-cotter]

It wasn’t always like that in the US. Three year doctorates are still a thing in the UK and in Germany. Lower the standards for a doctorate and make a postdoc a formal necessity for a job as a professor, rather than not formally being one but practically so. You can even call it a habilitation, like the Germans do. If you want a doctorate go for it. If you want to teach at university after you get your doctorate you need to basically do another one, but it’s called a habilitation.