I think it would be impossible to find the price point for a monthly subscribtion that would both be profitable to a provider, as well as attractive to the customer. If anything, as the customers would now be paying necessarily even a higher amount for agentic use, they'd make certain they'd be using the agent as effectively as they can, meaning it would be even more costly for the provider.

Pay-per-token is really the only way it can work. If some kind of fixed monthly price is desirable, then there should be a quota the user can assign, and then the agent could e.g. slow itself down by 50% when 50% of the quota is spent, another 50% at 75%, etc, to make it last longer..

As a side thought, I wonder how it could affect an agent's behavior if the information of this token usage/limit was brought to it..