"It used to be you wanted to marry up"

This quote by Victoria Principal is describing the idea of weding somebody that is of a greater social or economic status than oneself. In the past, it was common for people to marry a person that was of a higher class than themselves, in order to gain access to more resources as well as a far better way of living. This can be viewed as a method of 'marrying up' in order to boost one's own social standing. Nonetheless, in modern times, this concept is less usual, as people are most likely to wed somebody who is of a similar social or economic standing. This quote is likely describing the concept that this typical practice is no longer as usual as it as soon as was.