Do customers want this? ... not that Microsoft really cares.

For home use, I can see this being good as a large segment of users don't stay up to date on security patches, but what about breaking workflows in businesses?

Some businesses deliberately do not upgrade some software packages, because it would break stuff. It makes sense to just push all updates in a subscription based economy, but this could also quickly become exactly that: A subscription hell-hole where companies push updates and now you're old licensed copy of Photoshop is converted to Creative Cloud.

The idea isn't bad, I just don't trust modern software companies to be able to manage this in a way which makes customers happy.