This sounds a lot like the type of survival analysis mentioned in the other comment. The Kaplan--Meier estimator can be made conditional by, well, conditioning

This sounds a lot like the type of survival analysis mentioned in the other comment. The Kaplan--Meier estimator can be made conditional by, well, conditioning on earlier parts of the curve. If you count not "time-to-event" to "total-revenue-to-event" you get a lifetime value estimator!