However, the 'Retread' issue is not comparable between field managers and general managers. As has been beaten to death for years here, a field manager has very limited upward influence on his team's win total. A bad manager can make it worse, but even the best is completely constrained on the upside but the absolute talent level of his players, and he has little or no control over that. So many of field managers may be perfectly capable of winning but never do until they fall into the right situation.
A general manager is directly responsible for that talent level so team performance is much more directly his responsibility. I suppose a bad manager can mishandle a good team that a GM assembles, but in that case firing that bad manager is still part of that GM's job. The only thing that limits a GM is stingy ownership, but that is often pretty obvious to see from the outside. In fact, those are probably some of the guys you want to be looking at, guys from orgs with poor resourcing who show promise of being able to do more if they had better resourcing.
Tl,DR version. I mind a 'retread' manager who may not have won a lot less than a 'retread' GM. The 'win' burden for a GM hire is higher.