To emphasize this, Techmoan does thorough mechanical and electrical reviews of cassette decks across eras, and had largely critical reviews of similar new portable players and recorders, such as the We Are Rewind:
https://youtu.be/WleZGWAebsYMany—not all—of these criticisms are based on the fact that the only new mechs coming out now are the same budget Tanashin mechs from shitty 90s decks: https://www.youtube.com/watch?v=nezGOVOpHtc
This effectively sabotages any new deck, from a $20 Amazon white label portable to a $40 Walmart Sony to a $500 Teac with the same fundamental reliability and quality problems.
Unlike turntables, which demand precision but are fundamentally simple machines, cassette mechs are complex mechanical devices and nobody wants to make things like that anymore.