OK I can agree with your more-literal interpretation of "hold a candle"
I guess a better comparison, bringing it back to the OP / original argument, would be FA Cup vs. Europa League.
Sounds like Europa League winners make ~13.8 million pounds, while FA cup winners make 1.8 million pounds (AKA the amount of money Alexis Sanchez makes in a month).
So I could imagine that the FA cup would eclipse Europa League with the right prize money. I don't know if that transfers well to US Open Cup vs. CONCACAF second-tier league though, since part of that is that the big English teams are some of the most well-followed in the world, which is not true of MLS teams vs. their CONCACAF (particularly Liga MX) counterparts.