Atari had bad luck. They were more or less first with Pong — "more or less," because it's hard to say for certain they don't share that 1972 podium with the Magnavox Odyssey. The bad luck didn't let up after Atari's first computer, the Atari 800. Its 810 disk drive spent two years fighting an unstable spin speed, which meant Atari lost that particular battle to the somewhat pricier Apple II+ (both from 1979 — the Atari 800 in its base configuration was $999, the Apple II+ was $1195). I once asked Jordan Mechner (creator of Karateka and Prince of Persia) what made him pick the more expensive Apple II over Atari. Jordan told me he never considered Atari at all, because of its lack of reliable mass storage. That surprised me at first, but for someone with access to the kind of technology Jordan had in the US, not having solid storage — a disk drive — was simply disqualifying.
The bad luck kept compounding: the falling-out with the programmers who left to found Activision, the very poor decision to fight Activision in court, and effectively losing on that front too. By 1982 the Commodore 64 arrives and a price war kicks off — something new has to happen. In January 1983 Atari shows the 1200XL. Unfortunately its starting price kills it — $1000 at first, quickly dropped to $899, a price Atari would soon have to abandon anyway. More bad luck (or just a lack of foresight): unlike Commodore, which owned its own chip fab in MOS, Atari didn't. Half a year later Atari retreats from the 1200XL in favor of two models, the 600XL and 800XL, corresponding to a budget version of the 400 and a fuller version of the 800. And the cherry on top — the big reveal of summer CES 1983: the Atari 1400XL and 1400XLD, with a modem, speech synthesis, and, on the XLD, a built-in double-sided disk drive with room for a second one. Unfortunately, like the 1600XL, 1650XLD and 1850XLD, these computers never made it to stores.
So why "not Atari, again"? Same as with the code shown in Terminator, the popular claim that the Atari ST was first to support MIDI doesn't hold up either.
The Yamaha CX5M was the first computer with a built-in MIDI interface — 1984. Add-on MIDI interfaces followed in 1983, for the Apple II, then for the Commodore 64 and MSX.
DMS Drummer for the Apple II dates from 1983.