Would you move to a bigger house if you could just to have a better listening room ?

I agree with @feldmen4 and that ilk. I rarely "just" listen to an album. I could be eating or cooking in the adjacent open layout kitchen or watching sports on a muted TV or reading. My total open space is about 15x30, but not an ideal listening space with the irregular openings and windows on one side, but I have the speakers 3 feet from the wall so I have it set up the best I can. 

I could easily take one of the unused bedrooms (less than half the size of what I have now) and treat it perfectly, but I wouldn't listen to my system nearly as much as being in the central hub of the house. Luckily, my wife is tolerant and we have some guidelines, and she likes a lot of what I listen to, but has yet to touch the stereo (other than the volume knob) in 30+ years. I guess if I had a home theater dedicated room, I would try to accommodate a stereo system in that space. However they typically are in basements, and I don't want to spend my time above ground below ground.

House in Montana..

That would be a great adventurous move from New England. I would have to get Jokla parka from 66 North Iceland for those winters. This company makes excellent stuff. Recommended. I would also have to get used to driving pick-up truck. Not a big problem. Endless space over there.

No - I hate moving too much.

I do have a 13x24x8 foot space, unfortunately it’s the family room full of furniture so converting it would be bad for my health and wellbeing - self preservation is the higher priority 😉