Wow, you really had your thinking cap on today, huh? But of course you are right on target for what is happening out there. Not too long ago I moved closer to "town". When I was out farther in the country, I did a lot of my buying on the internet because it kept my fuel costs down and allowed me to "see" things that weren't for sale in town .... especially the older, used things like machines. Turns out I am still doing that mainly because I cannot find the stuff I want nearby. The whole of buying and selling has changed so much what with ebay, etsy, amazon, etc. that I doubt we can ever go back. CL has helped somewhat in being able to buy used things nearby but still, old machines and parts can be found all over the country .... well, world too. As long as there are people out there like you and others on the board and elsewhere who want and love the old machines, sewing or otherwise, there will be people willing to sell them. People who don't own a store or want to get involved in too much selling but are cleaning out Grandma's attic or buying stuff at auctions and yard sales will still need to have a way to sell their treasures.
Now that I have said we can never go back, I just remembered a news story that I recently heard about bookstores. It seems that the big stores are closing more and more but the smaller private stores are starting to grow. Turns out that they are determining what the local buyers want (and not just books but things like planners, notebooks, calendars, etc.) and stocking according to the wants/demands of the "neighborhood". I never thought small, private bookstores would make a comeback but ..... there you go. One never knows.
And hey, bellbottoms made a comeback and if they can, just about anything should be able to do so.