Affinity already has great Photoshop and Illustrator alternatives: https://affinity.serif.com/en-us/

The opportunity with Photoshop may not be to create another Photoshop clone, or add more features, but rather create smaller, specialized editing apps, that each target a subset of the Photoshop user-base, with perhaps less features.

Look at how Adobe Lightroom cherry picked a few Photoshop and Bridge components, to create a more specialized app that does a specialized job that Photoshop might have done in the past.

Or how Adobe's iPad Pro apps again deliver just a small subset of the total available features from their parent apps, making them more specialized for specific use-cases.

Photoshop's massive fragmented user base is ripe for the pickin' for sure. Could you tear down Gimp like that? Or would it be better to start from scratch?