Too much football for the players. The greedy leaguers that provide the big name players won’t wear it. The only way it could fit is if the regional football organisations like UEFA bin their tournaments like the Euros.
Keep it every 4 years for me. Every 3 years max and can the Euros not be some sort of qualifying phase for WC? Need to reduce the number of meaningless games also. The smaller nations (Gibraltar, San Marino, Scotland etc) should compete amongst themselves to see who are best equipped to play against the better nations.