I recall looking for a used E80 several years ago. Couldn't find one-on-one everybody holds on to them,like G70s Still don't see them often.
The E80 although having inbuilt speakers fell well short of the G70 and sales were not that great, so scarcity rather than just folks holding on is probably the reason you don’t see many for sale.
The rumours where that the sales were so poor it caused Roland to pull out of the TOTL Arranger market, fortunately the R & D that had been done for the G90 (Which was shelved) was incorporated into the BK7m module.
If you do find an E80 make sure it has the latest updates, as early ones sucked in the bass.
The biggest thing that stuck with me after the demos was that one of the film styles had about a 30 bar intro. (Ugh)
Bill