A PhD is too long, narrow, and frustrating to do just to get a slightly fatter paycheck.
For some reason, that deep dive clicked with me, and I’m grateful for all the personal growth that came from that. But for the vast majority of people, I think it could easily end as an exercise in frustration.
My BS took 4 years. My MS took 2 years. My PhD (computational physics) took 7 years.
I was the fast one at my school. Some of my peers (high energy physics, nuclear, etc.) took 9+ years.
Then again, I met my former business partner (not at the time) while in grad school. I was 2 years into my research, and he was a fresh new assistant prof in CS. About 9 weeks younger than me. Ph.D. in CS in 3.5 years.
In the UK and Europe, shorter PhDs are much more common, in part because you're expected to do a master's before a PhD.
Even for two or three years, I don't think getting a computer science PhD is a good bet if your primary goal is making more money.
I tell students to expect 5-6 depending on whether you want to go to industry or academia.
That’s true of Europe but it’s quite common to go straight from a Bschelor’s to a doctorate in the U.K. and many other former British Empire countries.
When I finished up in the 90s, the market was flooded with applicants from the former soviet union as well as locals. I remember speaking to people I knew on hiring committees who told me of 1000+ applicants per open tenure track position at tier 2 and tier 3 schools.
Around that time I was looking at the postdoc train, saw where it (didn't quite) led, and chose a different path.
The discrepancy here may be that "PhD time" in the US usually includes a masters, while it is counted separately elsewhere. That said, even if you break it down, my MS took 2 years and the PhD took another 5.
Between classes, teaching, and genuinely getting things done, it's not a fast experience.
Also, you probably arent making a ton more unless you go for an industry job...which is a little bit the opposite of the Platonic independence supposedly at the heart of the training method.
But very few people I know want to be a PI.
I took eight years but I also got married, worked full time, and started a company before I finished. By the time I graduated, the CS department had started taking a much firmer stance on timelines, with a desire for most students to graduate within six years or sooner.