Culture Points, a handful of missions then nothing?

In each of the playthroughs i've had I get a handful of missions and each mission i complete i get a point i can apply to my civ, but there only seems to be a handful of them, they're strongly based on RNG (like everything is in this game, which is pretty bad) then they no longer arrive. What's the criterion on their release?  is there only meant to be a dozen of them?   By about turn 250 each game (largest scale) is dead.   Are you doing statistical tests to make sure your RNG guarantee a non game breaking set of return values? tried on different cpu's?  or is this part of the intended design?

Most recent play through (Current) is on v0.77a.