Yes you could always go for the youngest body you could find, e.g. 503 series. I am often thinking about that. It would always be their relative freshness, not the extra features (gliding mirror, TTL flash), which are meaningless for me.
About the "value" of a specialist toy that is over 30 old - it has no value unless you are planning to sell it. A Hassellblad will give you years, if not decades of good times. Whether the body has cost you 500 or 1000 US$ does not make any difference at all, given the overall Opex of MF photography. It is just mental accounting.
A 300$ body is cheaper than one which does not need urgent maintenance just because of that. Seeking Alpha does not work on such things. Same goes for vintage cars and getting back into shape.