The problem is that programmers have way too many options to speed up their work, and few of them are premised around typing as the actual bottleneck - and the

The problem is that programmers have way too many options to speed up their work, and few of them are premised around typing as the actual bottleneck - and the split keebs, DVORAK etc. take a lower level of commitment than learning a chording system, so they attract the casual enthusiasts. There's a rabbit hole there that most will avoid going down. As well, chording tenses the hand more than single keystrokes, and so is not really advisable on a pure-ergonomics basis; the Kinesis Freestyle2 I use regularly(which is split) actively discourages chording by having its "fn" key be a toggle rather than a modifier. And then we look at "what can one do instead of optimizing typing". And it's mostly dull stuff that reduces error rates rather than increasing input rates. For example, installing some error-checking functions in your linter may take a few minutes, but save weeks of debugging time. So veteran programmers will tend towards deeply investigating that kind of thing over the gear porn. If you're inclined towards training muscle memory, you may want to put that energy towards the arts; some ability in technical drawing or playing scales has a relatively large payoff in expressiveness.