did vs -ed

In that particular question, I think at least half of the reason is about using the past tense "invented".
Btw, I think it was Alexander Graham Schwinn.

One major rule of English grammar is to "trim the fat". Saying "who did invent" is correct by most rules, but "invented" is the standard past tense of "invent". So it's a simpler and more efficient way of saying it.

if anything, using the standard past tense here is better for most terms.