It seems to me like a consequence of the ongoing unification of all software development related jobs.

In the ancient times, when you had separate roles for programmers, testers, system administrators, etc., all working in the waterfall environment, there was no need for a programmer to be on call. The programmers developed during their working hours. When the product was ready, it was tested by the testers. When it finally got to production, it was mostly bug-free. You had the system administrators on call, in case some server caught fire.

After the testers were mostly eliminated, bugs in production became more frequent. Continuous deployment into production requires continuous on-call duty. Devops means that the programmers are now also responsible for the failures of servers. Now the programmers are expected to also be agile in their free time.

(But of course, we are collectively all too smart and too proud to form a union. I guess we have to suffer the obvious consequences then.)

If you work on backend at a small to medium sized organizations, it is pretty common to be expected to own what you ship beyond landing pull requests: deploying, operating, migrating, oncall, etc.

(Yes)