*A hardware [[MIDI|Midi Port]]: this spawned a generation of Musician Geeks. And some Atari ST games did use Midi sound as an option. [https://forums.atariage.com/topic/301647-midi-games/ Source]
In fact, Atari was certainly thinking, you get the YM chip to make some noise, you want better you get MIDI gear. Trouble is YM is bottom of the barrel 'freebie' in the case and because MIDI is for professionals you are talking more than the cost of an Atari ST for a decent MIDI sound module so you are kind of stuck. The introductory price of the Roland MT-32 in 1987 was US$695 (equivalent to $1,920 in 2024).
The Atari ST is a paradox as it is inferior to the [[Amiga]] yet still considered better by many (the war still rages on nowadays). It was easier to do work on Atari, while on Amiga a guru meditation (machine crash) was never far away. Also the TOS was in ROM which means it could be used immediately on boot. And it didn't consume valuable RAM nor monopolize the floppy drive nor require an hard drive. And as the OS was immutable, less time was spent customizing it, freeing up more time to do productive work. The hardware was also simpler to develop for compared to the baroque Amiga architecture.