I'm old enough to remember Walkmans coming out in 1979, which was the start of the end of the boombox era. Approximately no-one was using 8-track at that point.
I'm not quite that old, but didn't people look down on cassettes due to their lower audio quality? Weren't most home systems (hi-fis) still vinyl or 8-track for a while longer?
https://public.tableau.com/static/images/U_/U_S_RecordedMusi...
In the USA, 8-track was always less than half vinyl singles sales, compact cassette exceeded 8-track's sales by 1980, and 8-track was dead by 1982.