Those specs are pretty exceptional, few tuners of the 1970s & '80s did as well as that, but in any event, specs like those were considerable overkill when the limitations were on the transmission side. I also wonder how well those tuners did, especially separation and distortion, after some years' use unless realigned.FM radio is severely limited by the characteristics of the transmission, not the receivers.
Your numbers are very pessimistic and plenty of tuners, from many brands left such specs in the weeds in the 1980s.
Here's an excerpt from the service manual of one of my 'better' tuners:
View attachment 158472
FM was great in the 1970s, before heavy processing, and when listeners were expected to be using decent equipment, and portable and in-car radios were mostly AM. When portable and car radios started offering FM, and radio stations started processing for loudness, it all went to rat-shit.
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