Nothing to forgive, we're all ignorant
The problem with switching to a new family of processors in my opinion is not so much that the apps themselves won't receive support. It's that the Intel versions of the app will become abandonware. Most Apple apps already have iOS versions--that's their future.
For years now macOS and iOS have been converging. Soon they will share processors. So the new Mac will probably get apps that are currently in development for the iPad, rather than a straight up port from Intel versions.
So, say, Evernote has iOS (tablet) and macOS (desktop) version. New desktop will likely have a beefed up iOS version, and old macOS might get some mercy care for a while but not forever... or will work only via browser.
That's from what I can see anyway... I'm not a software engineer, I don't work for Apple, I don't know what their plans are. I'm just "reading the signs" so to speak, and looking back at history.
Of course history won't exactly repeat itself because Apple is now a much bigger company than it was when it killed OS9. But we know they're willing to leave the past behind quickly to achieve future competitiveness. People say it's planned obsolescence but I don't think that's the motivation. It's getting to the future first--creating the future, in other words.
They want a seamless transition from house to desktop to tablet to phone to watch to headphone to self-driving car to etc... and they're willing to quickly dump what doesn't fit that current.
ETA: a good transitional move might be to switch to an iPad Pro plus accessories instead of a desktop mac. That works well with most generic apps already, but not so well with video editing.