You're not thinking. They made an app that users paid for that they expected to work for the whole time that they had it. If you pay for an app, you EXPECT the developer to update & continue to make it work with newer versions. These devs are just making a new app and saying, "Oh, sorry guys! You have to buy this new version which works with the new system updates."
That's like a car manufacturer saying, "Oh, sorry. This car you bought last year is not able to be driven on highways any more. You have to buy this new car to be able to drive on the highway now. Don't like it? Go build your own car." It's the stupidest **** I've ever seen and users like you are arguing FOR this. I just don't understand your logic.
I expect the developers to let the users who already paid for it upgrade to the new version for free. It's what the customers are expecting. Anything else is retarded.
It would be more akin if the US government decided to put regulations on self-driving cars, saying they had to have certain software installed and third-party hardware checks before they could be used out on the road, around the same time the Tesla Model 4 was released. Unfortunately, Tesla's Model 3 and lower with autopilot don't meet these standards set by the US government and Tesla can't upgrade older vehicles to meet those standards (remember autopilot v2?) due to logistical and money reasons. This means that Tesla will have to disable autopilot on all 3's and lower - it can still drive normally, but just no autopilot.
This would make you angry, yes, but it's necessary. Tesla isn't going to give you a brand new Model 4 for free nor are they going to upgrade your existing car. But now that there are known regulations in place, future Tesla vehicles won't have this issue. But that means in the short term, Model 3 and lower users are screwed. And what's Tesla gonna do? Probably give you $5,000 off a new Model 4 or something, or they may do nothing at all.
It's a similar thing with Samsung. Google and OEMs have decided to finally implemented a standardized way to installing overlays on Oreo. However, the new implementation is incompatible with Sungstratum. And for the mean time, Sungstratum users are screwed. But now that OEMs have decided on a proper way of doing overlays, this means that Andromeda will work for the foreseeable future and not a hacked up solution like Sungstratum/Samsung's Nougat implementation.
Not to mention, this money helps fund Substratum development. Ya know, the base app that can theme apps? The one that's free? That isn't free to them - servers, developers, they all cost money. If Subs goes, theming goes.
But if you really do want to use Andromeda for free, just root your phone.