If people were pirating Photoshop only because it was easy to pirate, my guess is when it came to professional work or another occasion where they had the funds to pay for image editing software, they would overcome whatever friction necessary to buy the best. That definitely happens in other cases like video editing where easy to access software is different than what studios pay for.

As a thought experiment: if Photoshop was means tested and free to anyone who couldn’t afford it, would that actually convert users when they had money?