It's exactly those managers that are the problem. They're incompetent and not needed for self-managed agile teams. So they keep rotating developers to safeguard their positions.

Meanwhile those managers are getting the salaries that better be spent on a team of great developers.

I think it is also how budget for hiring seems to be allocated. New funding round, hire a bunch, got budget approved, hire a bunch. Senior management and above seems to not like to give money with time conditions against their expectations.