[acqq]

"the one who said they built a Michelson interferometer in a day in their physics lab"

Maybe you should check with them too: it's possible that they have also built "a" Michelson interferometer (just like Thorlabs kit features one) but maybe their setup was in spite of that insufficient to perform the needed measurements in the way needed for the valid execution of a Michelson-Morley experiment?

Historically, Michelson constructed his first interferometer in 1881 in Potsdam, Germany:

https://arxiv.org/abs/2111.12176

Inventing it was obviously necessary but not sufficient for a valid Michelson-Morley experiment, which was correctly finished only during 1887 in Cleveland, Ohio.

[dekhn]

I think they must have said they built a michelson interferometer and not that they ran an MM experiment. Basically same as the thorlabs kit (in fact it probably was the equivalent of that kit, but cobbled from edmunds, since thorlabs wasn't really big at the time).