Hollywood's perfect woman is in her late teens and early twenties, which is why actresses find fewer roles past 30 and almost none past 40 except playing the Mom.
In contrast, you see professional and attractive middle aged women in British TV, like River Song of Dr. Who who is attractive and intelligent and held up as a role model in her forties or fifties. "Being Human" the UK edition had a plain late thirty something nurse - while the US version replaced her with a beautiful twenty something.
British TV does an excellent job of putting plain or even unattractive people as movie stars, like Professor Snape in Harry Potter, and older people in key roles other than the classic old woman role.
The US has far worse ageism that is reinforced by Hollywood's ageism, to the point that the evil stepmother is rarely played by anyone other than a beautiful and at best 35 year old actress.