As best I can tell, Sansui, Kenwood, and Pioneer all made some epic quality gear that was so good, they were easily above the capability of speakers of the day. If the speakers of the day were as we have now, it may have made sense to be more discerning but I am proud to own equipment from all three of these manufacturers right now. My brother had an A-60, back in the day, that sounded well adequate and it's from a line known to be well inferior sounding to the AU line. He connected it to some department store speakers and good to go.
I don't know anything about Fisher so I wont comment but some people I respect tell me Sherwood made some high end amps that would compete with anyone.
If you want to talk about tape, that changes things considerably. I'd say you should add Akai into the mix and you should remove the companies listed, except for Pioneer. Specifically, the Akai GX line with their glass heads were among the best.
There are a few Harmon Kardon cassette decks that were world beaters. They were as good as anything from Nakamichi, Pioneer, or Akai.
I will just say this about cassette decks... I've done endless A/B comparison of an HK CD391 vs a Sony TC-K630 and it took a long time A/B comparing with a pair of MDR-CD999 headphones (amazing headphones for the day and still hold up well) to decide there was an infinitesimal difference in favor of the CD391 using TDK SA cassettes. With Sony Metal Master cassettes, the two decks were either identical or an even smaller edge going to the Sony.
The Nakamichi Dragon cassette deck was a disappointment. Not because it was not great; it was. It was a disappointment because it didn't "blow away" everything else, as was the legend of the day in 1984.
I worked at an audio store in the 1980s and had a chance to audition a lot of gear, even taking some of it home. It was always a disappointment, with the exception of a few speakers that brought delight.
As best I can tell from my audio journey, brand allegiance is
mostly a religion. Get yourself a good pair of speakers and some high end components from almost any manufacturer and you will be good to go. If you want to achieve that last 1% that comes from selecting the absolute best of everything, you will spend a ton of money and probably ruin your enjoyment of music, but specific brands and models will rise above the rest, albeit just barely.
A local audio dealer frequently uses the phrase, "it was like someone popped a cork and the music came out!" to describe components, cables, just about anything, actually. What a bunch of BS. He was a B&W/Arcam dealer and yes, that stuff sounded amazing but you could connect a high end Pioneer amp from 1980 to those B&W and they would have sounded a tiny bit different but just as good. I will point out there were some amazing speakers from other companies, also, even back then. Snell comes to mind. I'm going to throw in Heco, although I doubt many in North America have heard of them.
By the way, one of the speakers that most surprised me was the Bose 301. Yeah, I know they are ultra-low end but they sounded OK, provided a bit of thump, and retailed at something like 250 bucks. The value was a revelation, back then. We weren't spoiled with excellent, cheap, speakers like we are now. Most of the low end stuff, sold with systems, around here in the late 1970s were "house brands". Invariably, the crossovers were a single capacitor. They were pretty crap.
Classic speakers take more of an effort to love but they can be brought to a pretty nice place for those who take the time to re-design the crossover networks and perhaps swap in a modern tweeter.
As best I can tell, you can select the brand you lusted over, but couldn't afford the TOTL gear of, as a teen, and build a system with that gear today, have a ton of fun building it, and end up with a really great system.