DVD/BD sales never mattered to begin with. Idk why people still think that. The studios aren't the ones investing money to produce the anime, it's the production committee. And they make profit through other means than DVD/BD sales.
Shueisha for example is usually in every production committee of Jump adaptations since they're the publisher of the manga. They get the money they invested back through boosted manga sales. So as long as the anime is boosting manga sales enough, there will be new seasons.
Music companies in the production company will usually in most cases make enough profit through the OP and ED themes, so that shouldn't really be an issue.
The only ones that actually care about DVD/BD sales are the studios themselves since that's probably their only income. But since they don't need to pay the budget for the anime themselves, it doesn't matter that much.