[kriro]

Counterpoint of sorts, taking German PhD programs as an example... You usually have to work on it for 3-6 years (many professors assume you'll use the full 6 years or it can't be interesting enough research), often times only being on 50% contracts making about 1k/month after taxes. Typically you only get 2 or maybe 3 year contracts at a time. And worst of all you're not really in control over this. If you run a startup you can at least theoretically influence your own income. Depending on the field your PhD skills are often considered rather worthless outside your specific niche. If you fail the PhD there's a huge negative stigma attached to it and your skills don't carry over which puts you in a horrible career spot. For most startups (depending on the country) it's fairly healthy for your career even if you fail.

Doing PhD research is basically a horrible job choice (imo).