Believe it or not, I agree with that. If one has a BM now or other gun that's not top of the heap, that's fine. There's things you can do if you feel it's needed. The most important thig is that you train with that gun. I won't recommend anyone rush out and buy one, but if you already own one, that's fine. Move up when it's time. If it's a duty gun, I would say it's a must to upgrade the parts at a minimum.
I'd rather have a shooter with a DPMS that fires 15,000 rounds a year than a gun owner with a Knight's Armament that only shoots 500 rounds a year if I had to fight. Ideally, I want the 15,000 round a year shooter with a KAC or BCM though. ;)
On a side note, here's a great interview with Officer Reston who took down the shooter with 12 rounds of 45.