We can get any where in less than 24 hours are there other advantages I do not know about. Plus the South Koreans are starting a movement to want America out. We should go ahead and do that. Stay out of their business - if they go communist - then snactions can jump in place of our military. My brother served two years in Korea - they have no positive regard for us.
We CANNOT send entire armored divisions anywhere in the world in 24 hours. In addition, bases in other countries give the military the logistical framework (food, gasoline, hospitals, clothing, bullets, etc...) to carry out military operations.
Did your brother conduct some scientific surveys of South Korean public opinion? I'm not sorry to tell you I'm not convinced by such anecdotal "evidence."