There is more to this argument. Adobe made themselves an industry standard with a perpetual license - pay once, own forever. Once they transitioned to a subscription model with a strict cancellation policy, it became the only option.
Saying that designers could have just continued using Photoshop CS on a 2006 MacBook doesn't reflect the reality of hardware updates and the changes in the industry-wide design trends.
The concern is here is clearly not the revocation of licenses.
The cost of not just learning but becoming a professional user of a specific set of tools is very high. Then later as time goes by being forced to either abandon these tools or to accept a different pricing model is - to many people - unfair and unethical.
Saying that designers could have just continued using Photoshop CS on a 2006 MacBook doesn't reflect the reality of hardware updates and the changes in the industry-wide design trends.