^ No, I have had this same arguement 1000 times in my career. Un-spring mass effect refers to the "un dampened" mass, or in order words, the mass that can not be controled. I understand this has been overcome with additional programming to correct for the linear motors own mass.
But this can also be overcome with geo, and I have designed heavy off road vehicle suspension that where as stable as small cars, in the past.
The demo I seen of the Bose system didn't have springs, but it appears there latest type has, but I would suggest still a total weight savings.
The key to what we are doing is the fluid, which as you likely have guessed, is compressable to some degree. This takes the place of the air/pressure system in the past. It is a hybrid of current semi-active controls and hardware, and the past work done on full hydro control.
The pump need only overcome input / efficent losses, not directly provide full forces. So as you may also suspect, the more bumpy the road, the LESS it needs work.
This is about as much as I can say Bob, but I think you get it
I REALLY want to try it with a rally car, given I will soon have my medical back, thanks to a cornea transplant procedure I have recently undergone.
(Will get my flight medical back soon as well)