I'm also a grad school dropout, so I have a bit of perspective on this as well.
You're correct, IMO that the PhD is largely about training to become a junior researcher, and less about making an original contribution to science. But, based on the dissertation defenses I've attended and theses I've seen, I would say they are less "conservative" than "scope limited." Many people I know have gotten two years worth of papers out of their dissertation topics.
This may be field-specific, however (I was in math).
You're correct, IMO that the PhD is largely about training to become a junior researcher, and less about making an original contribution to science. But, based on the dissertation defenses I've attended and theses I've seen, I would say they are less "conservative" than "scope limited." Many people I know have gotten two years worth of papers out of their dissertation topics.
This may be field-specific, however (I was in math).