The problem with the $4000 salary threshold was that it was too low - releasing players off of teams where the owner had done nothing more than log-in, twiddle the roster a bit, and never logged in for another 5 weeks. Since players of that quality were being given out to new teams, there was no reason to make them FA (especially when some weren't even drawing a bid).
The idea behind player recycling is that the aggregate talent level across BB should not change due to owners quitting, or joining up, but only through training, drafting, decline of skills, and lesser skilled players retiring. If Mark Cuban gets bored, and doesn't log in for 5 weeks, the Mavs players won't retire, they'll go to other teams.
Most of the players on team that are being bot-ified are quite ordinary, and can simply be given to new teams. You could do the same for more elite players. The risk is that some lucky new owner would get a major windfall. So instead, you make these players available as FA. If some team buys an $8000 player, they are going to sell a $6,000 player, to a team that will sell a $4,000 player and so on down the food chain until some new team fires a player with a $2000 salary, who can either be given to another new team, or retired from the game.