The real main point is: how much control users of commercial routers could have with a reasonable effort (I mean, I know most are GNU/Linux machines, where the OEM sometimes respect the GPL providing the sources but there is no easy custom build and rom flash with very few exception like the little GL.iNet devices).<p>If the router is just a person mini-computer with some *nix OS and it's config, directly tied to a media converter from the ISP it's a thing, otherwise it's essentially next to impossible doing most of reasonable actions including properly probing the internet-side for a small potatoes audit.<p>Some countries have mandatory free router choice, like Italy (curiously), where at least the user is allowed by law to run it's own router so ISPs are obliged to give all settings, VoIP included, without making like of their customers needlessly harder, but that's not true in most countries. Some ISPs (i.e. Orange France) run arbitrary custom solution to makes people life harder if their put another router behind the ISP provided one. People choice is very limited even for those who would know and want to run their own home/SOHO LAN.