There are other reasons to buy or love an instrument, as you can see looking at my collection. But seriously: have you ever seen MIJ Fenders with some of the flaws I've shown on my 70s US Fender basses? And mine are two examples of the better ones.
MIJ Fender instruments can have and actually have defects like most mass-manufactured things ... the first 2/3 years of Squier JV production may have likely been characterized by a tangible higher quality level which, however, reduced transitioning towards MIJ Fender with subsequent re-negotiations of the original agreement's terms ..
On the other hand, yes, there surely are bad examples of MIA Fender production in the 70s (especially from 1976 onwards), but there are also good instruments for sale belonging to that period .. personally I would not invest too much money in a late 70s Fender instrument .. whether or not a given amount of money may be judged adequate for a 70s MIA Fender and not for a MIJ Squier JV or viceversa basically depends on the perception the market has concerning the value of the two lines of instruments, looked at along a given time-frame ...
However, I'm under the impression that the used instruments market constantly needs the generation of new "heroes" in order to preserve a certain margin of profitability for the die-hard operators of the sector .. hence, after the celebration of the greatness of the 60s and 70s instruments, which were defined as the "vintage" ones, now we witness that of the Squier JV ones, immediately followed by that of the Fullerton-era AVRIs ...
I personally would have to get exceptionally good feelings in playing one of those instruments to pay what the used market's sellers want to receive from the sale, but i think that a jazz bass or a P bass are a jazz bass or P bass now as they were in that period ... the bridge, pickups, electronics and necks of the contemporary Fender MIA's production are better than what was installed on the same instrument models at the beginning of the 80s, for not to talk about the finish, aside from that of the instruments which were finished in nitro ...
The prices are surely hyped, that's why, notwithstanding the inherent quality of the Squier JV basses, I would not buy anything for more than 450Eur belonging to that series (slightly more for Fullerton-AVRI instruments unless they are in a true NOS condition) ...
)