In fairness, comcast (big US ISP) allows you to buy your own cable modem. However, they are terrible for multiple other reasons that would not fly in Europe (data caps, lobbying to resell browsing history, opaque pricing schemes, etc)
Sources:
https://arstechnica.com/tech-policy/2009/12/comcast-throws-1...
https://www.cnet.com/news/fcc-formally-rules-comcasts-thrott...