How it works
Why software warranty?
Any product bought in the European Union has a limited warranty: if the product breaks or misbehaves during that period, you can either get the product repaired or replaced, or you can get your money back.
The duration of the warranty usually depends on the type of product. It is reasonable for a smartphone to last at least 2 years, but a banana probably wouldn't last that long. For software, however, there is no determined duration of how long software should "reasonably" last if you buy it.
How can we fix this?
If you buy an app from an app store, it should work - and if it doesn't work or if it becomes unusuable after a while, you should get your money back.
We should start treating apps and software like products: if you pay for it, there should be a warranty. Experts should determine how long an app should reasonably work, and then those warranties need to be legislated.