Excellent post, and you offer a well reasoned argument.
World 9-ball Championship is the toughest. Tied for second are the US Open 9-ball and the China Open 9-ball. Fourth would be the All Japan Championship.
Still, there is much truth in your post. For an aspiring pro, it's probably a harder journey to the Derby City Master of the Table title than the others, because one must learn to excel in all the American fringe games in which very little money can be made competing compared to nine ball. That said, for the limited number of Internationals that have bothered to learn all the American fringe games, they have succeeded beyond their wildest dreams. DCC Master of the Table, once monopolized by American players, has been dominated by the Asians, who have won eight of the last nine.
I can definitely see where you are coming from. Master of the Table is super-tough to ever achieve, and for most non-American players, it's impossible as the American fringe games are not played much by all but a few overseas players.
I have never seen a player from China at Derby City but your suggestion that they fail when they come to the US is uninformed. At the last US Open 9-ball in 2019,, Wu got to the final and Liu Haitao, who previously had a third place finish at the US Open, tied for 5th. You observation that American players rarely go to the Asian events has only become true in recent years, and it was a direct result of sustained American failure at these events. The last time an American won one of the three overseas giant field multi-stage majors (World Championship, China Open, All Japan) was when Earl won the World Championship in 2002.
Still, there is much truth in what you have posted. It may take even greater commitment to the game to win DCC Master of the Table than any of the majors.