For digital copies, they could bury this into the EULA and make it a requirement that you agree to it before you make your purchase (IIRC some storefronts do this already).
However for physical copies I suppose there could be a case made if the duration of support was not disclosed at the time of purchase (or it was not printed somewhere on the outside of the packaging).
I use both. Pi-hole running in a docker container on one of my home servers which my gateway is configured to assign as the default DNS for all clients, and uBlock Origin on all my browsers to catch everything else.
Pihole is pretty good at catching ads on platforms that are not suited to browser based blockers (IoT devices, streaming boxes etc) but it isn’t perfect and is best used in conjunction with another solution.
Solution: don’t read that shitrag. It was always a waste of paper, now it is a waste of bandwidth as well.