I think part of it, well for me anyway, is I love having a back-up so I'm never w/o a machine.
But also those old ones are so wonderful! I've gotten really interested in old machines. They are workhorses.
You're right about room though. I need to get another table for my old ones. A Featherweight is small though and very portable. I can use mine anywhere or take it to a class.
Also for me it's a little like my fabric addiction lol