Everything has limits, of course. But if you've not yet seen a deceleration, it's reasonable to expect that at the least you're in the middle of the sigmoid, not the top.

in the absence of a stalling signal. it's better to assume exponential and work backwards than hope the next bottleneck is impossible.

this gets more nuanced because "the sigmoids won't save you": https://www.astralcodexten.com/p/the-sigmoids-wont-save-you