How do the new 4 strokes keep up with 2 strokes?

I have a 2000 KX 250, and my dad has a 2007 yz450f. Many people say that " 2 stroke 250's are basically the same as 4 stroke 450's". I hate to go against 2 strokes but my dad and I raced on a straight wide open trail. In my first 3 gears I had a nice lead but once we hit the 5th gear it felt like he had an extra gear over me. They just have way more horse power and speed, where 2 strokes are mostly acceleration and quickness. But if you put for example a cr 500 vs cr450f the cr 500 2 stroke has about 6-10 horsepower over it.

to be honest i dont know how they do it. but i rode a `125 then got my 250 and i would pick the 250 every time the power differance is just amazing. i havnt had the pleasure to ride a 450 but the 250 2 stroke i rode only had a little more power over my 250 4 stroke so idk how they do it but they do it and do it well.

there just building them better, now they have 4 stroke powerban more torq and acceleration. they are just building the engeins bigger with lighter frames no steal now its like aluminum or titanium

the new honda crf 150 can keeep up with an rmz suzuki and other bikes like an yz honestly i dont know how its just buitlt with more porwer and tweaks