We consider a variety of factors when determining what plans to make different features available, and we do revisit those decisions from time to time.
I could see a world where it is available on a lower plan, but we need to take into consideration whether appropriate limits are in place between different plans, and the cost to support our customers on each of them.
For the time being, aside from the options of upgrading now or hosting things yourself, another to consider is to first prove out the value of your community without a subscription model, and then layer that on later, once you’ve done so.