Enterprise sales are where the revenue for the $1T valuations comes from. If they were forced by competition to offer subscriptions to all those organizations, they'd blow up tomorrow.
My personal ChatGPT account is a Business account with 2 seats at $30/ea (minimum 2 seats required).
Why? Because for $60 you get ChatGPT Pro, significantly cheaper than the $100 normally required for the next level personal plan!