It's a lot of work and time, and most companies don't particularly need PhDs. Maybe a PhD gets a boost in pay starting out, but 5 years of experience cancels out most of the benefit. I suppose PhDs can get a shortcut into Prinicple or Senior roles, so there's some tangible benefit.
On the other hand, if a company is hiring PhDs and doing research, I feel those jobs are most likely to get cut if business is going poorly.
The money stifles. There's not enough money for everyone who wants a Very Large Array of their own. People don't have money to sit around thinking all day. There needs to be some system of deciding priority. The profit incentive is the only reason any science dependent on HPC and GPUs is possible. If you want more science, you need more economic growth.
I don't think that's a thing. Some government job will use a pay scale that varies based on your education level, but fast-tracking someone in software engineering because they got a PhD seems questionable seeing as the skillset does not really overlap.
It's a different thing for corporate research labs, where usually you need a masters for entry-level and PhD for the level above.
My sense is you might get paid when you start what an undergraduate makes after one year and a pay raise.
Your career will probably develop faster than the person who started working after undergrad. Your ceiling is likely hire.
I don't have a PhD, but this is what I've observed.