The problem with that is you are only considering the dinosaur mass extinction. There have been at least 5 mass extinction events in the history of earth.
One of the other was believed to be caused by the eruption of a super volcano, which could happen these days. If Yellowstone were to completely erupt it would wipe most life off of the earth.
Another possible extinction event is an astronomically close supernova. Which would strip our ozone layer and the sun would do the rest.
Not to mention a nuclear war or a rogue planet moving through the solar system (could throw off our orbit or very unlikely hit earth).
Can humans survive some of these events? Yes, but how long will it take for the earth to be habitable again is the more important question.
Also don't forget that an underground society is going to need to use lots of energy to keep the lights on for plants to grow and it will need a way to get clean water. So, we may have enough supplies for tens of years or maybe even a couple hundred or so, but will the earth be habitable (reasonable climate, decent oxygen levels, ozone layer to protect from the sun, ability to grow plants) again that soon?
What always survives these extinction events is multi-cellular organisms deep in the ocean, which can eventually reform life on the planet. In the last mass extinction event small mammals survived just under the surface of the earth, but that is not always the case.