According to this article, the last Mizzou Arrowhead game was a financial disappointment. The Tigers played BYU and only 42,000 showed up. Is BC going to be that much better of a draw in seven years? We know BC fans won't buy a ton of tickets. If this is a make good to Arrowhead (as the article implies) why are they making good on a game nine years after the first problem? Should a make good come a little sooner?
My guess is Missouri doesn't want to move any conference games to a big, relatively neutral area where other schools might recruit. I also assume they don't want to move any cupcakes to a big stadium they can't fill. They probably don't want to lose homefield advantage against any other Power 5s that agreed to a home and home. BC is probably viewed as respectable enough draw without being a recruiting threat nor a team where they need a huge homefield advantage.
What does BC get out of it? Maybe a slightly higher guarantee and perhaps slightly lower travel costs. In the end, this is probably good news for BC. We just have to wait seven years for it to come to fruition.