Nico, surely you've realized that encouraging people to jump in NOW would only exacerbate the problem you're seeing, right?
As to my own experience, my cheapest pin buy was an EM in 2016 - and wow but I miss that game (Prospector). The machine I also arguably overpaid the most on was an EM (one of those "oy this was a mistake I really should get out of here but let me make nice to not get shot" deal) yet I managed to break even / profit just a little even after my repairs, etc. They certainly seem to be all over the map in terms of value and asking price BUT, recently, I've noticed no pinballs (EM and solid state alike) asking under a grand go wanting for long, no matter how old or how bad.