I think the real turning point is when there isn’t the need for something like photoshop. Creatives that I speak to yearn for the day when they can stop paying the adobe tax.
There will always be an adobe tax so to speak. Creatives want high quality and reliable tools to be able to produce high quality things.
I could imagine a world where a small team + AI creates an open source tool that is better than current day Photoshop. However if that small team has that power, so does adobe, and what we perceive as "good" or "high quality" will shift.