As a younger sibling of two myself I do have some sympathy with Harry's plight as "spare".
It's not confined to aristocratic families. I was annoyed by the narrative some years ago about Ed Miliband "stabbing his brother in the back" by not subsuming his own independent political career into David's.
I also feel the same about those younger siblings born into dynastic farming, fishing and other business families who aren't going to inherit the business but are expected to provide cheap labour at least until they can get away to lead independent lives, which may lead to estrangement from actual family for not "pulling their weight". There's a difference between being a willing participant in a family business and simply wanting to remain close to your family.
I feel even worse for those whose very existence is to be a source of organs and tissue for a chronically ill older sibling. where emotional pressure may be brought even into adulthood to forgo an independent life.
Rejoice! Chancellor Healey Will Give Us Cheap Marmalade & Gherkins.
Cash, should we have some on us?
The Israeli election, will Netanyahu stay in power?
Aricle on what it's like to work as professional psychic witch

but I've finished now (although the stairs need doing and the decorations need to be put in the attic).