Also, some companies and teams do versions of this, officially or unofficially. One pre-FAANG tech company I worked had a policy (known among the local schools

Also, some companies and teams do versions of this, officially or unofficially. One pre-FAANG tech company I worked had a policy (known among the local schools) that each new hire has to "pay your dues" on grunt work, before you get to do fun/glamorous work. That kinda worked for them. A problem they had was that they were doing desktop development in C and C++, which, among other purposes, had to ship software bundled with new brand-name PCs (so not necessarily able to bugfix over Web later). The real problem was that very few new grads are minimally competent at production-grade C or C++. But, in early Web years, the company couldn't hire enough experienced software engineers to relocate to a college town. So they had to try to train and retain local grads of a top CS program. That might've been part of the thinking behind "pay your dues"... before you get to make rookie mistakes with greenfield.