Like someone said earlier it could be 10-15 years. Probably not, but at least 1 year. They will look at how many other CC's you are opening during that year. I would say 1+ year if no other inquiries and spend goes along with income. They do look at MS and say this guy is charging 5K a month but only takes home 3-4 K after taxes. Now you're a high risk and maybe that's what happened? Your short credit history also hurt you, my bet is if it was 10-20 yrs nothing would have happened.
Both Chase and Amex will do soft pulls every few months to keep a eye on there investment.