My journey to, and acceptance of, the 20ga came after 40+ years of hunting and shooting. I started out hunting with a shotgun at age 14. It was a JC Higgins bolt action 16ga. A couple of years later I was bequeathed an Ithaca® LeFever Nitro-Special™ 16ga SxS. I hunted everything with that gun; deer, doves, ducks, geese, grouse, pheasant, quail, rabbit, squirrels, and turkey. In about 1976 I bought a 12ga H&R® single shot in KMart®. I was a young Staff Sergeant in the Army but had a wife and two kids and money was tight.
Two years later I made Warrant Officer (WO1) and went to Europe. There I purchased a Browning® Liege™ BK-26 12ga skeet gun. By the time I retired as a CW3 in 1990, I had a whole passel of shotguns in 12, 16, and 20 ga. I had O/U, SxS, single shot, pumps, and semi-autos. and I shot skeet, sporting clays, and hunted with all of them.
In 2008 I had to have my shooting (left) shoulder replaced and my surgeon told me my days of shooting a 12ga were over. HE WAS RIGHT. From that day forward all of my shooting and hunting has been with my 20ga guns. Now I shoot just as many waterfowl and upland game as I did before and I ain't going hungry.
Now next month I will be 73 and have suffered the effects of age, mileage, and infirmities. I will stick with the 20ga. With all of the 21st-century improvements to shotgun ammunition, I certainly DO NOT FEEL I AM UNDERGUNNED WITH MY CHOICE OF GAUGE!