The .45GAP was another answer to a question nobody asked.
A shorter .45 case to allow for a smaller frame, while allowing .45ACP-like specs. The thought is that modern powders will allow it to perform like the .45ACP.
Unfortunately, nobody was really bitching about the size of a standard or hi-cap .45ACP frame that much.
If a little suburban matron like me has carried a 1911A1 for 30 years with no problems, what's to complain about?
If it ain't broke, don't fix it. Sometimes it's just the marketing geniuses trying to promote a product.