As a former Marine with ANGLICO, I have called in a fair number of CAS missions (and even a few SEAD). Five minutes is quick. Before I explain at all, I want to bring up the idea of game versus reality. Most of us play for enjoyment and not for training. As a result, many would be rather put off by making this too real (I mod for Armed Assault and OFP in the past and can speak from experience here). Players want to have the 'illusion' of realism without any of the real bother of making it real. Calling in a real air strike is complicated, time consuming, and there is very little room for error. In a game, people want to be able to click on a map, wait 30 seconds (or less in games like BF2) and then see some really pretty visual effect. I think CMSF does a great job at providing a much more realistic environment than BF2, but it is still a game.
Ok, with that out of the way, let me explain about real CAS. First, it does take time - more than most people think, even after watching CNN. If I have several aircraft 'on-station' I will be able to get the first bombs on target in about 10 minutes (+/- depending upon a wide range of variables). On big difference between games and reality is Dash-2. That is the second jet that trails behind the first by 30 seconds or so. After Lead's bombs impact, the FAC makes immediate corrections for the second plane. If additional runs are needed, the jets will egress all the way back out to the Initial Point. This is miles and miles away. You then have to go through the entire call for fire again (9 Line) and then get the aircraft back on station. Speaking from experience, time goes much MUCH faster in real life when you are trying to coordinate, communicate, track the target, and not get killed. So, ten minutes or so in real life is pretty damn fast. In game, 10 minutes can be an eternity. The game doesn't take into account the myriad of other variables (running low on fuel, losing track of the target, weather, other units having priority, other aircraft in the area (interrupting bombing runs), comms going down, inexperience or human error, and the list goes on and on.
So, I recommend that we enjoy the speed at which we can call in such firepower.