Did some research
Apparently many preferred conventional/wringer washers over the various twin tub units for several reasons.
First there was the matter of transferring wet and possibly heavy laundry from wash to spin basket. With a powered wringer you just feed things in, guide, and that is that. With a twin tub you've got to not only get all that wet laundry into the spin basket, but you've got to arrange (and possibly rearrange later) things so load is balanced. Even then the thing is likely to shake and vibrate, sometimes often violently.
Other concern was size of twin tub units. Wringer washers could be easily rolled out of the way into a small space if necessary. The various separate tubs (if used) could be packed away between wash days as well. OTOH these twin tub units were rather large and thus took up real estate.
Whatever the reason you see far more older wringer washers about than vintage twin tubs. Probably the most commonly found (aside from the smaller Hoover and Maytag units) would be the Easy spin driers. There because that company remained with format longer may have something to do with things. As noted GE, Norge, ABC, etc... all pretty much abandoned twin tub washers either before WWII or shortly afterwards.
