Just don't use services that use DRM. They will stop.
However, distributors who are in between end users and publishers have more influence. They voting with their wallets (by refusing to sell anything from publishers which require DRM) has way more significant impact on the publishers. That's why services like GOG are really positive game changers, while others like Netflix are making things only worse by obliging DRM sick publishers.
Of course my main hope is that if enough people demand DRM-free ebooks, they'll give up. So the first thing is to absolutely boycott DRM-laden books. Therefore I won't post the search URL here, ask the support for it, be noisy and state you're actively boycotting DRM :)