I don't think anyone ever thought of it like this. Well, some dumb managers probably did. If you want to eliminate QA people, then you need an enormous automated E2E test suite. To have that, you need dedicated people who think of and write those test...one would call it a QA team.
Want to save in project management? Just make devs responsible for planning and estimating, and call it "agile".
Want to remove sysadmins and ops? Make devs write their own configuration for the infrastructure, and say you do "devops".
Want to eliminate QA? Say that you do TDD.