Help Understanding Rear Suspension Bushings

[Best4x4xFAR]

So I took the X5 in for an Alignment Check. It's way out from where it was four months ago when last done, Front Right toe is now NEG .2, right rear NEG .1, camber at -1.8.

Truck hasn't hit any bad potholes, or been driven on rough roads. Kind of concerned its so far out after four months of essentially highway driving.

But the issue now is that they can't adjust the rear, saying the bushings are seized and won't move. They took me out and the tech showed me as he turned the wrench on the rear lower adjustment, the busing just flexes.

First it seems odd that they were not seized 4 months ago. There is little if any corrosion on the underside of this truck, and its been summer. And of course their parts diagrams show the entire lower arm needs to be replaced at about $750 in parts per side.

I see FCP shows replacement bushings, but the RealOEM diagram doesn't, so I guess BMW doesn't offer the bushing separate.

But as I look at the options, it looks like that bushing is pressed into the arm, so I guess they are saying the Eccentric Bolt is frozen in the inner part of the bushing?

If so, wondering if there is another way to address it, some way to replace the eccentric bolt?

She is coming up on 100K miles, and I'm sure it would be best to replace all the suspension bushings, ball joints, etc. But its not really an expense I want to take on at the moment, but I don't want to eat the tires either..

Thoughts or suggestions?