I think that streaming will become what most people use. You will be able to buy downloads if you want, but why buy a download if you can always stream the same album with the same quality?
Bandwidth for streaming and storage capacity keeps increasing for the streaming sources while cost continues to go down. My internet provider allows me over a terabyte of data a month now.
They have the thorny problem of sorting out who gets paid what while keeping the service at a cost that listeners will pay, though. Musicians will have to get paid fairly for their work or they’ll quit recording music.
Digital sound quality will keep improving for a long time to come. No need to get into a digital vs analog discussion.
I think that artists will still want to make albums and people will still want to listen to them. There will always be a market for singles as well. The future of digital audio looks good to me.