The gedolim, by and large, do NOT support this theory, and even more so, they emphatically do NOT support the solution offered.
Some do, and some don’t, support some of the proposed solutions, but I find it hard to believe that many don’t “support the theory”. You acknowledge that the starting point in shidduchim is four years apart. Is there any evidence to suggest that the actual gap id significantly less? Almost all available evidence (anecdotal and otherwise) suggests that there are indeed many more girls than boys. It’s silly to pretend otherwise.
Right now, the only ads I’m seeing are suggesting that boys consider going out earlier, and shadchanim redting to them earlier, if their parents and rebbeim feel they’re ready. What’s the harm? Are you against them following their rebbeim? If their rebbeim are against it, it’ll be as it has been, with the difference perhaps being that the boys are more open minded to girls closer to their age or even older. Again, what’s the harm? Nobody is forcing anything on anyone.