Who's to say country X won't nuke you out of the sky before you have a chance at mining those materials? Whether we like it or not, international politics will dictate the course of humanity when it comes to space, unless some isolated group manages to do it in secret.

Further, even if a group manages to secure trillions of tons of common materials for us today, who's to say it will be given out for free? If it is, well, maybe I want you to give my country a bit more of the share than other countries, or I'll take their share by force. Even if we emerge a united world after something like that, we may find that we've developed far superior technology that has no use for the materials you've acquired.

There are tons of real-world questions that have to be answered, and it doesn't matter if we don't have time to come up with a good one, because someone will pull the trigger first.