IMO it's not offered more because it's not user friendly to most customers; they have to do more math to figure out what their costs are (not as transparent, takes a little more effort to know what monthly cost will be, what if usage is not known, etc.)
If a company offers metered pricing like this and a competitor offers a similar functionality at a flat monthly rate, the latter is usually perceived as the more user friendly experience.
I think in some instances it makes sense but not always. There was an essay someone linked on HN a few weeks or months ago that was written a while back which touched on this exact issue... on the wrong computer and can't find it rn
If a company offers metered pricing like this and a competitor offers a similar functionality at a flat monthly rate, the latter is usually perceived as the more user friendly experience.
I think in some instances it makes sense but not always. There was an essay someone linked on HN a few weeks or months ago that was written a while back which touched on this exact issue... on the wrong computer and can't find it rn