The dirty secret is a lot of them come through "residential proxies", aka backdoored home routers, iot devices with shitty security, etc. Basically the scrapers who are often also third party, go to these "companies" and buy access to these "residential proxies". Some are more... considerate than others.

Why? Data. Every bit of it is it might be valuable. And not to sound tin foil hatty, but we are getting closer to a post-quantum time (if we aren't already ).