Honestly based on the photos this looks like they are hoarders.
I picked up my vintage phones at antique shops and thrift stores though, because internet prices are too high. Unfortunately, I can't get my rotary phone to work with my ATAs, even the ones that are supposed to; it works on POTS, but local POTS runs $60/month. I'm just not that committed, also not willing to pay for a pulse to tone converter. My newer old phone has tone dialing, but only on jacks with proper polarity; I might be willing to buy one of the components they made to rectify (hah) the situation, that's missing in my phone even though the model label indicates its there.