The problem is a six month delay pushes everybody's launch back six months. So if you had an interplanetary probe scheduled for the next Mars launch window in

The problem is a six month delay pushes everybody's launch back six months. So if you had an interplanetary probe scheduled for the next Mars launch window in April of 2018, a six month delay starting today would mean your probe doesn't get launched until the next window in July of 2020 unless you have enough clout to bump other launches.