Got myself a Nakamichi BX-300, and I'm kinda blown away by how decent it is. With the price old 80's cassette decks go for today, it seems like you could produce a fairly well spec'ed machine for ~300 and have it sell. Agreed though, most of the stuff produced today is rebadged white label junk; go to a thrift store and pick up something second hand, it's probably better.
Cassettes on the other hand may be another story though, I don't know if the chemistry allows for old metal tapes to be produced anymore.
People in my social circle know I like cassettes and often funnel old collections my way. I just received a box with 85 vintage cassettes. Probably 50% will be unplayable from warping of the outer shell (these are often pulled out of an attic or storage with annual cold/heat cycles). A further 20% won't sound very good.
However those that are in good shape typically sound terrific. The quality of the player is key (most currently produced cassette players are truly awful) and older machines can easily be brought back to life in most cases. Sony's old high-end walkman's are also magnificent for playback.
Metal tapes are hard to find new, but i have repurposed used ones to great effect. I would like to emphasize that even the boring stalwart type 1 cassettes can sound really good. The quality of pre-recorded could be incredibly inconsistent fresh out of the wrapper back in the day and I think this gave them a bad reputation.
Some of my vintage Beetles cassettes, and Peter Gabriel cassettes had extremely high production standards and really hold up. "Peter Gabriel's "Security" was digitally mastered and sounds fantastic.
I was watching the new film "Nobody" and the main character steals a hot rod with a cassette player and rocks out while driving. The rattle of the old cassette and sound of it loading really hit a nostalgia nerve but it was plainly cool. This kind of thing appearing in new media might be one reason people are going back.
After the 80s expired, in Germany, long-form audio dramas [1] transitioned from being produced to vinyl to cassette (the transition to CDs happened amazingly late in the 2000s, and for quite some time both cassette and CD were typically released at the same time). Basically, all my audio dramas are cassette or vinyl.
What I was running up to say: whereas the quality of CD masterings typically was consistent and befitting the medium, many of my audio drama cassettes have quite varying physical qualities. It esp. gets noticable with long-running series such as the "three ???" series; over 100s of cassettes, you can make out the slumps and peaks.
It really is a shame that replacement products that are up to par do not really exist. You'd probably have to persuade a local enthusiast or skilled audio electronics repair man to restore an old deck for you unless you can do everything yourself should you get one. At least, the cheap consumable mechanical parts like belts are available for any make and model under the sun, so keeping one deck running with some care is something even non-enthusiasts can do
Cassettes on the other hand may be another story though, I don't know if the chemistry allows for old metal tapes to be produced anymore.