The phrase "cookie-cutter blonde" has been around for at least 30 years, but I suspect that much of the homogeneity you note these days is due to plastic surgery.
Which I find kinda sad.
Drew Barrymore used to have a distinctive look. Pretty, but with a kind of pudgy face.
She has apparently had very extensive surgery and is now a generic cookie cutter blonde. Doesn’t even look like herself much.
I think it’s sad, too.
On the positive side, I suspect her career has tanked now that she’s generic.