There we go again, technical solutions that doesn't actually solve the problem, yet works for the individual with the right technology :)

Jokes aside, besides just outlawing telemarketing as a whole, there are "bigger" solutions that can help more, like the opt-in "do not call" registries that bunch of countries have, that actually work, and works across landline/mobile phones, regardless of OS or manufacturer :) I'm not sure those lists exists in every country, but every country I've lived in (so far) has had a variant of those, that works.