>but it's not really good for your career

Can you define that with more specificity? I find that academics have a major blind spot where good career means "the path I took" to the exclusion of all other paths.

>Speaking as someone who has graduated over a dozen PhD students in computer science

And your CV says another 6 dropped out. What was good for their careers?

He appears to be tunnel-visioning on academia.

The vast majority (>75%) of Computer Science PhDs leave academia. [0] Becoming a "world expert in a specific topic" is overfitting skills for a sub-niche of a specific career. There certainly aren't enough jobs in academia.

[0] https://academia.stackexchange.com/questions/213640/what-rat...