Now, do I sell the beat-up MP-32s or buy another bag to store them in?
It depends... Do you think you'll ever use them again? If you sell them, maybe you can buy yourself something nice to go with your current setup.
On the other hand, let me play devil's advocate to my own response...
I have the same Toney Penna Ironmaster putter I bought around 1963. When my putting infuriates me, I pull out that putter to use for a round or two. It makes me concentrate a lot more to use it well and when I get my stroke back, I quietly tell it thank you and stick it back in the closet.
Maybe those beautiful old MP-32s could do the same for you one day when you need to work hard to get your swing back.