Just like CDs and LP records, there will always be a market for them, but no where near what their rates were at the height of their respective popularity and sales numbers.
The thing is we need (and also to get the younger generations below us to be motivated as well) to make sure that Blu-ray discs and DVDs will stay profitable enough, similar to CDs and LP records, so that they'll always be made.
@SamuriHL just now added more facts above my post here to what I'm saying, so I'll defer to his expertise on the subject.