To follow your analogy to its silly conclusion, some breeds have a tendency to accumulate vet bills. Don’t buy the dalmation if you are trying to save money.That is a great way to look at it. Who cares if the initial investment is different by a few hundred dollars. If you end up going to the same vet, buying the same food, using the same same kennels, the cost of the dog is the same. Claiming that one letter league is more expensive than the other is just another case of the pot calling the kettle black. If you are traveling outside of your county for league games, and have mandatory post/pre-season events, your soccer costs are likely the same as those participating in the other leagues.
Take a look at the game history on Soccer Rankings. If the club’s older teams go to a lot of out of state tournaments, then expect to pay for them as your kid gets older.