I'm having a bit of an issue with the term. Under normal conditions, hydrogen can be a gas. Oxygen too. But these are elements, not a complex molecule like THC. As long as it's intact, it's still a liquid (or an oil, if you will), only with enough kinetic energy for us to inhale conveniently.
Again: every liquid evaporates all the time. Take a glass of water and watch it – even at room temp, a significant amount will eventually be gone, just takes some time. In the case of THC it evaporates too slow for us to inhale because under normal conditions it doesn't have enough kinetic energy, so we have to increase its kinetic energy by increasing its temperature (basically temperature *is* kinetic energy). But it's a much more gradual procedure than what those charts suggest, because they only show the temperature where *all* thc molecules have enough kinetic energy to evaporate (and again: in a world without air pressure...). It creates such a misleading narrative of all the components being neatly divided by their boiling points, suggesting we could precisely enjoy a certain component by choosing a certain temperature on our vape (and avoiding others by avoiding their boiling points). And that's just totally not the case.