You saying it's not possible? I don't see why not, just need to look second hand.
I sold some old Whatmough Opus floorstanders for $250 a little while ago (which I do actually regret ) and I've just seen some of the bigger brother ones going for $350. Lots of reasonably priced bookshelfs floating around too, some B&W 685s on gumtree for under $500, but I guess the room is probably on the big side for that.
Lots of old NAD/Rotel/Cambridge integrateds floating around for a few hundred bucks too. Grab a cheap CD player and a chromecast audio (for when you can't be bothered walking from the bar to the CD player) and away you go.
Sure it won't be a showcase system, but I tend to think the biggest improvement of all would come from room treatments, that basement looks like it would be pretty damn live.
I had an interesting conversation over the Phone last night from a friend that used to work for LG and he told me regarding why 75 and 86 Inch models that do not have nano technology and his answer is "nano Technology Models do not respond as well on Dolby Vision as the 75 and 86 inch models without it".
Hummm Interesting! See the nano models have a Enhancement film on it and run brighter,,,,,, I want to know more about this and I was told where to get this info. He also said you wait until you see Dolby Vision it blow away anything that HDR 10 has done in testing.