No downsides that I can see for the consumers.
Sadly we have since started seeing all big companies move to a SAAS subscription-based model so in practice it seems to become less relevant with time as it's only meaningful on software under perpetual licenses.
But at least Windows Server is still a big one that can save a lot of money -and that can also help struggling/downsizing companies by allowing them to sell licenses they no longer need.
However, maybe people will see the light and go with free software instead (as in freedom, not beer, etc).
Unfortunately, it doesn't necessarily work for "entertainment", because entertainment is consumable. You always want new music, new movies, new games, I don't think we've found a way to make those free (libre) yes.
Making something a lot of people want and charging them for it is an awesome feature of copyright law. I don't want it to go away.