There are "live" residential proxy IP lists you can purchase today from a variety of companies. Various companies defending use them as an additional data point when making a call to throw a captcha or block.
ISPs have been fairly silent on the topic (it is a hot topic for many of them due to the kimwolf botnet leveraging resiproxies to function and launching attacks). In many cases, being a resiproxy is a violation of the TOS - but they struggle with enforcement and how to do customer engagement given that most resiproxies are loaded without the end user knowing. So you have an educational problem - how does an end user figure out how to remove it.
Some ISPs could null the resiproxy c2 infra - and a few have played in that space.
Home router vendors could play their part and notify users exactly which device is connecting out and give them an option to isolate, etc.
My biggest issue with IP brokers is how they'll avoid taking any responsibility for their customers action. A fair amount of bullet proof hosters (and we're talking malware distribution, botnet c2s, ransomware c2s, proxy/scanning) get their space from brokers. When you engage with the brokers they say go talk to the transit providers - and because the bullet proof guys can switch off to another transit provider easily they maintain connectivity/continue to operate. Super common in Europe where most of this goes on and they have a super plentiful transit market - but they are still rolling with the same set of IPs they get from these brokers (and one in particular).