I wouldn't call using 1% of the mass of Mercury to create enough living area for a quintillion people and using most of the energy our Sun produces anyway to be analogous to anything you're alluding to on Earth thus far.

But the point here isn't to dive into the moral issues. It's not even to ask what MOST civilizations would do. It's simply to ask would ALL civilizations restrain themselves this way? If the answer is "no" then we'll find at least one. Saying no civilization would engage in this kind of growth when it looks entirely possible seems like far more of a stretch than the scenario I outlined.