That's a big can of worms, since it applies to approximately 100% of all software. You only ever buy a license that allows you to use software, almost never actually buy software.
You can still offer limited-time subscriptions, of course, and you can extend the minimum deadline for your server-dependent software to free as often as you want, just make sure people know what the deal is when they buy your software.
DVDs and other media also aren't yours to buy, they're just licenses and a physical container to use that license. You can buy software the same way you can buy a DVD, and you can rent software the same way you can rent a movie on a digital storefront.
So what kind of transaction is buying(2) something? What do you get in exchange for money? It's clearly not a good, so is it a service? Is continued permission to use the software a service? Then if that service is interrupted the consumer should be entitled to some kind of reimbursement from the provider, right? Because otherwise the provider has an incentive to stop the service.
This should be criminal. If the sale copy says "buy" "own" "purchase" then they must not be allowed to remove your license to that content by any means.
I'm fine with them removing content from storefronts. I'm even okay with them saying "you're responsible for your downloaded copies, if we decide to discontinue licensing you won't be able to redownload". I'm not fine with them saying "buy" "own" "purchase" and then coming in later "oh we decided to change the licensing situation and so you no longer have access to what you have 'purchased'". That is theft, more than copyright infringement ever could be.