It means shows that don’t get picked up by the studio making the show can get picked up by other studios to air it.

Two immediate examples I can think of:

“House MD” was produced by NBC/Universal but aired on FOX

“For All Mankind” was produced by Sony but currently airing on Apple TV+

How are the incentives any different now? Why would Amazon not want to be paid for a show it does not want but Apple or Netflix does? Swap around any of the company names.

If a different studio was selling to Apple/Amazon/etc then presumably they would have language that lets them sell to someone else if they did not end up distributing it.