[themagician]

Software and hardware move too fast now. Even if you buy it, there is no guarantee it runs properly in 4-6 years for whatever reason.

If Apple had LTS versions of their hardware and software that guaranteed backwards compatibility for 15 years that be great. But now they will drop or replace an API or function within 6 years that breaks your application—almost guaranteed.

I have spent thousands on apps and games that require VMs or other hacks, or simply no longer work at all. At least with a sub you can cancel when it gets shitty or no longer works.

[imoreno]

It's hard to guarantee what will happen in 5 years. Even if the vendor was really principled, who will honor their support commitment when they go bankrupt?

Instead of a "guarantee that it will run properly in 4-6 years" you should be looking for "guarantee that you can find a workaround when it breaks in 4-6 years". Avoid lock in, proprietary formats and protocols, poor compatibility, requirement for exotic platforms... Many DirectX games work great in Wine. It's the ones that do crazier tricks that are harder to deal with.