Arguably the most important commercial applications on the IBM PC were written in assembly: Lotus 1-2-3 and WordPerfect.

It was a competitive advantage early in the 1980s, then turned into a handicap by the end of the decade when the performance and memory tricks didn’t matter as much as graphics and GUI.

True: people rolled their eyes at anybody trying to field a commercially successful product not coded in assembly. Languages were for proofs-of-concept, and for toys. And yes, that changed as 1990 approached.

There was a lot of BASIC, but at least on microcomputers, there was a lot of assembly (if you needed any performance).

I was writing games, and there could be a bit of BASIC wrapper, but the rest was assembler.

Ditto here. C, Pascal and Forth were what I was using in those days. I did some 6502, 6800 and 68000 assembly, but only when needed.

Likewise; I wrote a lot of Fortran in those days.