There's this thing called the rule of three, and while it means a lot of things, one of them is that a gag or joke is usable about three times before you get diminishing returns. There's ways to keep jokes fresh beyond that, but it gets increasingly difficult.
I can't help but compare it to the one about the kid from the village of heroes, which has a near identical premise. Wildly op child wants to be a knight in spite of a ridiculous inferiority complex. Which is still fairly funny after 9 chapters, where this is becoming aggravating after three. That might be partly because of the release style though.