You are just basically forcing your interpretations of the series onto others. That only make sense to you, but the author stated completely otherwise. He clearly stated and implied this series to be a mix of feudal and modern era. And lol at saying those things are only shown once. Are your comprehensions that low to the point that Kishi has to reiterate the same things for you to believe what was shown? If your favorite character has shown a certain jutsu only once, that means I can dismiss it just because it was shown only once?
Things aren't going to stay the same. You should have realized this ages ago. I may not like the sudden outburst of skyscrapers. But I can definitely see why that's the case. Especially if you are comparing our capabilities to the people within that verse. NxH and BlacLord summed it up real nicely.
Btw, it's over a decade.