We implement rate-limiting and queuing to ensure fairness, but if there are a massive amount of people with huge and long queries, then there will be waits. The question is whether people will do this and more often than not users will be idle.
If everyone in a pool uses it during the ~same periods and sleeps during the ~same periods, then the node would oscillate between contention and idle -- every day. This seems largely avoidable.
(Or, darker: Maybe the contention/idle dichotomy is a feature, not a bug. After all, when one has control of $14k/month of hardware that is sitting idle reliably-enough for significant periods every day, then one becomes incentivized to devise a way to sell that idle time for other purposes.)