I would agree, in the 70's mid-fi focused on sounding good for the money, in the 80's they started to build to a price point, it became about maximizing profit margins and living on their reputation, stuff from that era is hit and miss. In the 90s it was about home theater. Few companies wanted nor cared if you bought two channel, they wanted you to buy an wiz bang AV rig with 5 speakers and a sub.
IMHO
If looking for good mid-fi: audition Marantz, Denon, Yamaha, NAD, Cambridge Audio, for pieces that are more recent up to 90's Pioneer from the 70's and, very early 80's. Early 70's Sony and Sansui.
One currently produced option may be Outlaw the have reasonably priced stereo receiver that has been favorable reviewed.
One final thought, as far as mid-fi goes, there are a lot of options. Stuff from the 70's will give you the widest selection. However there are companies such as
Vincent, Music Fidelity, NAD and Cambridge Audio and Outlaw that do provide good sound for the money. I would not rule out those. Hope this helps and Happy hunting.