> But anything in life where you "just show up" and fulfill some explicit assignments tends not to be very valuable.

Including paramedic or trauma surgeon, where the explicit assignment is to stabilize the human being in front of you?

Or how about plumber, to stop water where it shouldn't be, making it come out faucets and go down drains where it should? Had furnace issues when we switched it on in October, the HVAC technicians made the magic box generate warm air: his explicit assignment was 'make the house warm' and he showed up and did that.

Depends on your goals. Even as a plumber you have to think about what's worth what, how you specialize, and what the price is. Even as a doctor you may be under appreciated and the explicit goal is not so explicit all the time and sometimes curing the patient requires inventiveness and not only following a script or a textbook. The patients survival is often not purely a cookie cutter application of rules as it works in school.

And in some sense we can make the PhD requirements explicit too: prove that you are able to provide valuable and novel contributions to the scientific community as recognized by them. But it's not box ticking. But so is becoming an especially appreciated and respected doctor in your city. It's not just don't kill too many patients and you're golden.

If you want a mediocre run of the mill PhD it's not super hard. It is hard, but not super hard if you have academic aptitude. You can do something incremental and follow the trends, and eventually some venue will publish it. Not many will read it though and you won't become a leading voice though. There are many incremental paper that help many average PhD students get their degrees.

There are plenty of other non academic fields where you have to work hard and long hours, such as finance or law firms. You can choose less demanding alternatives too but they are less prestigious. Of course finance pays better.

I think the problem is that people want to treat a scientific career as both a regular job and also as something of a pop star personal brand type of thing, and they only want the upside of both.

There are many problems with academia, power balance etc of course. It's not unlike problems for aspiring movie stars or in other somewhat isolated bubbles within society like in sports or the theater scene, or how kitchens work in high end restaurants etc etc. If you want to become an acclaimed top expert in a subfield, it's not easy. And humans are going to do their human things around such opportunities for status advancements.