So what if rates stay elevated? They shouldn't/can't keep their balance sheet this bloated forever. The FED currently holds ~2.7T of MBS that they never should

So what if rates stay elevated? They shouldn't/can't keep their balance sheet this bloated forever. The FED currently holds ~2.7T of MBS that they never should have purchased in the first place. That is damn near ~25% of the all outstanding MBS in the US (!). In the short term anything can happen, but longer term there will need to be many investors with a big appetite for MBS to suck up that supply without rates surging higher. Oh yea, these "dumb money" investors will also need to ignore the current all time high valuations and record low home affordability.