Essentially, there's been a shift in shooters. Forgive my bluntness, but most people simply can't shoot well.
Law Enforcement agencies have reduced firearms training distances - in the '70s and '80s I carried a revolver and had to qualify out to 50 yards. Now I'm issued an 'eighteen convulsive snatch special' and only qualify to 15 yards. Other agencies have done the same, claiming these are 'realistic' ranges. The reality is, the marginally trained troops can usually qualify at these ranges.
Real citizens follow the trend. Actual shooting skills are decreasing in general. Not long ago, I read someone in a firearms forum saying how he was doing pretty good at 5 yards, but at 8 yards his rounds were all over. Eight yards? One could die of smoke inhalation or powder burns at that range.
Please understand, I'm not disparaging or making fun of that person. One must start somewhere, no one is born a shooter; it comes with training and practise. However, low expectations and standards produce low end results.
NRA Bullseye is losing popularity. Why? Two reasons, it's not as much fun as running across a firing area shooting randomly and it requires too much work. There is a great deal of effort involved in firing a pistol one handed at 50 yards. That effort pays off later in all other forms of handgun shooting, but it's hard and requires work.
A six shot double action revolver using the 125 grain .357 Magnum load is still a substantial man-stopper. Nothing is guaranteed, but that round works a whole lot better than most others. The trick is, one must actually deliver a 'hit' with that round. Details, details, details...
This isn't intended to be primarily insulting or a random flame attack. But I see a serious lack of marksmanship among newer shooters in general. Nor do many newer shooters realize how poor their skills really are. I must finally point out, marginal skill levels do not improve under stress. If you think your groups are bad at eight yards now, try it with your life in immediate danger.
The GAP and SIG rounds might be nice rounds, but I'd be willing to bet that (Leaving the .38 Super out of the discussion) the users of any one of the "old timey auto," calibers far outnumber the users of both the GAP and SIG together. I've got a feeling that in a few years, both will wind up on the same shelf with .30 Luger and .38/200. 
