>>213927159 (OP)
There's a few factors in there:
One, it used to be extremely common to cast people way younger than they actually are. A lot of people point to labor laws, but they could have still cast 19-20 year olds in some of these parts instead of 30+ year olds. My theory is it's just a carry over from theater traditions, where casting wasn't too concerned with realism, but as movies have gone on it's started to shift away from things like that.
Two, people just in general age much better. Even if you weren't a smoker, up until the 2000's you basically lived in a 24/7 smokebox, "non-smoking sections" weren't even a thing in a lot of places. Skincare in general is also much better, better sunscreens and lotions can keep you looking youthful far longer than the norm.
Three, its also less about actors "looking older" as much as actors that look younger is what's popular right now. Popular looks change all the time. In Victorian times, someone being pale was considered attractive, and a woman being on the heavy side was considered being full-figured. In the 50's people liked their women skinny with a nice tan, and their men looking mature and masculine. Right now the trend is youthful and pretty, people like women with big asses and men extremely chiseled, but like all things, in a few decades that standard's probably gonna change again, though who knows where it'll go from here.
