Rival synth makers agreed on MIDI by building the cheapest version

By the early 1980s, synthesizer manufacturers each built their own proprietary way for one instrument to control another — Oberheim's system linked only Oberheim gear, and every other maker had its own closed scheme. Musicians who wanted to layer a Roland synth under a Sequential Circuits keyboard, or sync a drum machine from a third company, simply couldn't; each brand's instruments were an island, and the arrival of affordable home computers was about to make that isolation worse, not better.

The straightforward engineering path for the companies drafting a shared protocol was to build the most capable one their 1983 electronics could support: continuous polling for expressive detail, wider data words, room to grow. That was also the path several early proposals took, calling for faster transmission and richer resolution — the obvious way for competing engineers to prove their own instruments' features mattered.

They built the cheapest possible spec—slow serial, event-driven, 7-bit words—so any maker could afford it, making universal adoption self-reinforcing.

Cheap implementation meant no manufacturer had a cost excuse to skip MIDI.

Universal adoption in the first year gave every company a stake in the same network.

No one could defect to a rival scheme because the shared network was already ubiquitous.

The more instruments spoke MIDI, the more valuable speaking it became, reinforcing adoption.

When standardizing across unequal competitors, design for the smallest player's budget, not the best possible spec, because adoption breadth beats technical capability.

Every synthesizer maker, including the smallest and least capitalized, could afford to add a MIDI port, so the whole industry adopted it within the same year the spec published rather than splitting into rival camps. Dave Smith later put it plainly: MIDI "works because it's simple and free... which led to it being ubiquitous." Forty years on, the 1983 spec is still the operating standard for electronic instruments worldwide, natively supported in Windows, macOS and Android, and new MIDI gear still talks to 1983-era hardware without modification.