In https://admin.google.com/ac/appslist/additional, enable the option for "Early Access Apps"
In this particular case, I would guess (I have no inside info) that companies are sensitive to use of AI tools like Bard/ChatGPT on their company machines, and want the ability to block access.
All this boils down to Workspace customers are companies, not individuals.
The smart move would have been for workspace accounts to work exactly the same as consumer accounts by default, and then something akin to group policy for admins to disable features. For new stuff like this, let the admins have a control for 'all future products'.
It may not be the option we like as tech-aware users, and I've found it annoying in the past at a previous role where I was always asking our Workspace admin to enable features. But, I don't think it's the wrong choice.
You're on a business account. Businesses need control of how products are rolled out to their users. Compliance, support, etc, etc.
It's not really fair to cast your _business_ usage of Google as the same as their consumer products. I have a personal and business account. In general, business accounts have far more available to them. They often just need some switches flipped in the admin panels.
It's not surprising that products and services are launched late (after more lawyering) or not at all.
Ideological policies often have a side effect. It's worth the inconvenience only some of the time.