Neither of these are actually needed, all that is needed is to be able to disrupt the pipeline of jobs that interns/junior developers would normally build their initial skills on before moving on to more senior positions. Cutting these entry positions out means continually fewer replacements, and less talent (a deflationary trend, the limited number of positions acts as a filter, and its not necessarily merit based).

Without replacement, eventually older more senior developers will age out, retire, and then everyone will panic but by then it will be far too late (its already cascaded).

If it is not economical to develop or maintain a skill set, the knowledge involved becomes lost knowledge when that population dies out (as we all do given sufficient time).

A perfect corollary is the repair of electronics in the US. There might be 1 person per population of 100-200,000 that goes into business for this sector. If they get hit by a bus, its no longer locally available, and mortality happens to us all.

This is one of the main structural problems with burning bridges in blind marches towards some idealized progress.

How can you go back when all your competitors do the same thing and its no longer economic to run the business except by following the same doom loop as your competitors.