But not everyone has access to all of your browsing history; especially across browsers and devices.

There's Microsoft, Google, and/or Apple have that. The profit models of these big companies create some disincentives on onselling this data.

AV providers are often on much smaller margins and the return from selling this data or building their own products on it is much higher.

I wouldn't be surprised if ISPs and VPNs also sold on data.