King George V worked diligently to restore the formality and discipline that his father had let slide at Court, but after the Great War and the dawn of the Jazz Age, high society was having none of it. Dancing the floor with swinging tails was a feat that only Fred Astair could master, most preferred their more comfortable dinner jacket. Edward VII may have been royal patron of the dinner jacket - the big man did prefer comfort over stuffy tradition - but it was never intended as a replacement to the tailcoat, and was to be worn only at the most private of dinner parties where no reception followed.
It was not Edward VII but the future Edward VIII who, by regularly opting for the dinner jacket over the tailcoat with his aristocratic circle of friends, played the pivotal role in its elevation to standard evening wear. Thus the formerly de rigueur tailcoat ensemble became relegated to extremely formal functions while the previously informal dinner jacket which had been considered too vulgar for female sensibilities was promoted to standard evening attire.
A Parisienne with such sensibilities and with a good many thoughts on this wrote in Vogue magazine way back in 1922 to impart that men are dressing worse, not better, and the substitution of the dinner jacket (read: "Tuxedo") for the tailcoat is an example of the slovenliness to come.
"You are entirely wrong in imagining that we pay no attention to the way men dress...The truth is that while we may say nothing, we do not in the least consent, and we find, messieurs, that for some time now you have been very much changed, and for the worse."The slovenliness came alright. We can all blame the dinner jacket for that and the long decline in male elegance.