It's not so much intelligent life arising that matters... what matters is that they become galactic explorers. Really, there is no obvious reason why any species would want to do that, least of all resources. Besides... maybe life is more rare than that, or maybe intelligent tool users are very rare. After all, a genius that lives in deep oceans of some kind might as well be a clam for all that it might change a life off their planet.

You need a specific formula, and you need to include, "Does not extinguish own existence" at some point between, "Gets tech" and "masters galaxy and becomes threat to all life in universe". That really sounds more farfetched than just... the kind of competitive organisms that make it as far as we do, die off for one reason or another before they dominate a galaxy.