Earlier quoted context omitted.
You do have a point, but this trope is overstated in a way that doesn't reflect reality IMO. At a competitive level the playing field is completely level. You have to assume players have access to all the cards, otherwise games like it make zero sense. Sure, it's an expensive game, but so are many other games and sports. It's an accessibility issue, not a balance issue: it's not like you can buy your way to victory.…
You've demonstrated that only the rich can compete; not really refuting the point, is it? But limiting our attention to strictly pro-level play is a bit silly, as it ignores the overwhelming majority of players. When I was in high school, two of my friends had a lot more money than the rest of us. We'd get a few boosters of a new expansion, they'd get a case. Consequently, their decks were nigh unbeatable.
But then isn't that how Football works as well. Star players get rich but who really gets rich is the company called NFL.