Honestly, what got me away from cheap plastivacs was that they weren't that cheap (we were spending $200 every other year on a bissel or whatever) and they spent as much time "sort of working" and "broken" as working well. This was around 2005ish. Actually, it was my mom back then buying the vacuums, and I don't recall why we were spending $200 or so for them - were there no $50 ones, or maybe she just figured that a $50 vacuum was never going to be any good.
I honestly don't know if the masses will buy a $199.95 vacuum over a $200 vacuum because it's "cheaper" or if there's some sort of "close enough for the real thing" that you just step up.
I'm kind of amazed by the niche Shark has today. It would be understandable if they were $80 still, but I'm seeing many at $250 or so. That's very close to enough to go to a vacuum store IMO. You won't be TOL, but you can likely get several entry level vacs for less than double.
I guess for me, "cheap" is only a quality if it's actually noticeably cheaper. I'll compromise if I can get it for 50% or less of the "real deal". But when I'm at 70% or more, I always wonder if I'm actually saving anything.
None of that works for the DTD $2k + systems though. And I'm not at all sure there's actual value there for many people. I mean, you might need a Vacuum, but do you need the 5 other things a Kirby does? Does it actually save you space over dedicated tools? Is it as good as the dedicated tools?(Probably not)...