I'm not suggesting Formlabs would do this, but advertising the $79 add-on and then making very few of them available would be a way for a manufacturer to look open while actually not supporting openness.
There no reason for FormLabs to limit supply of the $79 tanks, it would also limit their ability to sell their more expensive resins to Studio 1 customers, and also removes a clear pathway to get people to upgrade to their more expensive machines, capable of working with their even more complex, and expensive, engineering resins.
I'm not saying I hate Prusa here, I'm saying that limited availability is a common practice to drive hype.
Versus a company like Bambu who seems to ramp up production now, in advance of selling the product.