Wow...for a thread just started yesterday, there have been alot of comments! DH and I were at an estate sale yesterday and he and I just had a conversation similar to this. I think many people enjoy collecting machines for the same reason people collect other items such as milk bottles, depression glass, etc. And, many have machines that do have meaning to them, as well.
I currently have my grandmother's Singer treadle machine. G'ma was born in 1901. I have never bothered to look up when the machine was made..doesn't really matter to me...it is the sentimental value of it. My DSIL has my mom's Singer..she rarely uses it and I hope, if she decides one day that she does not want it anymore, she will let me have it or at least give it to one of her girls. I have my late MIL's embroidery machine...it is a dinosaur and I will use it as a trade-in when I get around to upgrading. And, I have my Viking Lily that I love....not a fancy machine at all but, one that has excellent stitches and I enjoy using.
I stay away from purchasing other machines. At the estate sale yesterday there were 4 machines (one was a Singer treadle, and the other 3 were various older machines (40-50 years old). I did not bid on any (and they went cheap). Personally, I do not have the room for them and, as I told DH, I would rather save my sewing machine money for the Viking Diamond or Ruby that I have my eye on. That said, My DFIL has mentioned that there are a couple sewing machines in cases out in one of his barns. One of these days, I am going to check into them...hopefully, there might be a Featherweight hiding out there!
I truly believe it is up to the individual. I love reading posts from those who are so excited over a 'find' but, I also understand those posts from quilters who are not interested in acquiring old machines.