One thing that's been largely ignored in this stuff about the miseries of being a 'spare" is that between 1830:and 2022 the only times the monarch was someone who'd been first-in-line when they were born was between 1901 and 1910, and a few months in 1936. "Spares" have normally been the ones that inherited the throne.

It's interesting to note how primogeniture is a lot more the way of the world than just in the context of royalty and aristocracy. Remember how, when Ed Miliband went up against his big brother Dave it was widely seen as a stab in the back, just not done. Most especially by Dave, who stormed off to sulk in America rather than just buckling down and bing ready to serve loyally in his brother's cabinet, as would have been expected of Ed if the vote had gone the other way, and which is what other defeated candidates mostly do. And that was seen as quite reasonable behaviour on the part of Dave,.

And I don't think it'd be reasonable to see that distortion as being a matter of spilling over from monarchical and aristocratic primogeniture and infecting English society. More deeply rooted than that.