Im 180 and weigh 73-74 atm, at 190 it would become pretty hard to build muscle.
That's actually not true, shorter people do not gain muscles easier than taller guys.
It's mostly that if you have shorter limbs it's easier to look more "thick" and compact.
Let's say there are 2 skinny guys with a similar body structure, but one is 170 cm tall and the other is 190cm. Let's asume that after x time they both gain 10 kilos of muscles, who do you think would look "bigger" ? obviously the 170cm tall guy would look more "buffed up", because he has "less space" to distribute the mass he gained, his muscles would be thicker and wider, he would look more "compact" if you want , but that doesn't mean he has more muscles than the taller guy, because they both gained the same amount of muscle mass.
That's why pro body builders are generally short, it's hard to find Mr.Olympia level body builders taller than 180cm. Shorter guys can look more thick with less mass.
"The reason bodybuilders are short, is, as others have said, because it's easier to fill out a smaller frame. Why? Because your limb length is shorter, and you're building muscle at the same rate. Therefore althought it is technically the same amount of muscle, the illusion of the smaller frame makes it appear larger. "
i woulnd't call it "illusion" tho, because they are actually wider-thicker.