I love finding vintage ads for machines I have in my "herd", and looking at the prices. I do similar calculations, bkay, and am always surprised at what an investment people were making into these machines. I guess that hasn't really changed too much though - modern good-quality machines go for over $1,000 too, easy. But from my perspective, it's always a little bit of a trip when I buy a very nice old machine at a thrift shop for $30, and then find out that when it was new it cost someone the equivalent of what I paid for my first car.
Then I think about housing costs of that era, and think about that ratio - what they paid for a sewing machine vs. the price of their home...
No wonder they were so decorated and stylish, and placed into nice cabinets that were posed in prominent positions in the household!