Too many products/businesses use "Open" to mean "You can use it if you pay" rather than "you can understand how it works" or "you can look under the hood".
OpenAI is just another example of a typical SaaS business misusing the word to make themselves seem "nicer" than they are. Ultimately, it's a for-profit business and it will operate as such, shouldn't surprise anybody.
If you want a SaaS model, you should have all of the things that the SAAS model supports including premium pricing and enterprise tiers, OpenAI needs to get their act together on DallE2 as no serious business use case will use the consumer pricing and hacked together unofficial apis.
Maybe we differ in how we understand what "SaaS" really is (a debate which is as old as the concept of "SaaS").
For me, if you offer something software-y behind payment, and the software can only be accessed online, it's a SaaS.
No need to offer premium pricing, enterprise tiers, support or anything else. Putting up a online API/UI that is locked behind payment, it's a SaaS (in my eyes).
OpenAI is just another example of a typical SaaS business misusing the word to make themselves seem "nicer" than they are. Ultimately, it's a for-profit business and it will operate as such, shouldn't surprise anybody.