I'd say his upbringing played a large part, the average individual has been ranking higher on the narcissism scale with each passing year. In the past, entering relationships was something you did for your family and society as much as it was for your own happiness. That changed for better and worse, resulting in a sexual revolution in every 1st world nation followed by a growing abstinence.
Today's youth are actually having less sex than their parents were 30 years ago, despite the evaporating social stigma surrounding it. Maybe you could say that this is due to everyone's higher standards in a world that demands you be 110% satisfied with your partner, maybe it's due to increasing narcissism, maybe it's the autism in the water.
What we can say is that noble families usually produce shitty offspring, because when you tell a child that they're destined to do Great Things, they interpret it to mean that hard work and persistence aren't necessary in life. Studying and practicing things are for other, lesser talented people. So not only was Elliot given high expectations, he wasn't equipped with the toolset to meet them.
The problem with narcissists isn't that they love themselves too much, it's that they're incapable of loving anyone else. People assume the story of Narcissus is about a guy who fell in love with his own reflection and ignored everyone else until he starved. Which is wrong, he was rejecting everyone's propositions long before he saw his reflection. He didn't love anyone, and then he fell in love with himself.
