> no one has come up with a satisfactory solution

Plenty have proposed a satisfactory solution.  No one has come up with a solution that is satisfactory to *you*, because you have overconstrained the problem.  The reason we still have no utctotimestamp() after all these years is that you, and you alone as far as I know, refuse to accept a method that inverts utcfromtimestamp() with microsecond precision over its working range.  Such a method is a perfectly reasonable and acceptable solution and would add a lot of value to Python as a language.

I suspect you don't realize just how much pain you have unintentionally caused the world of Python users by singlehandedly blocking progress on this issue.  I've seen them: students, friends, coworkers -- even very smart and capable people are stymied by it.  No one thinks of looking in the calendar module.  Maybe if you watched some of them struggle with this, you would understand.

> leave it as an exercise to the reader to solve

To take this perspective is to miss the point of Python.