The Swedish monarchy is considerably diluted but because Sweden is a very egalitarian society, that is acceptable. Britain is the opposite and one of the ways that the current Royal family are sold is because it is not diluted. It was very important for the Queen to marry a prince. Camilla Shand's father was an army officer but to the best of my knowledge not aristocratic and certanly not royal. The closest that she can claim royal association is that one of her grandmothers or great grandmothers was Mrs Keppel who was mistress to Edward Vll.
At some point, when there is enough dilution of royal blood, the general population starts asking the question, 'Why can't I do that job?'.
Granted, Camilla's background is not highly noble, but like many people today, she can trace her lineage back to as much royal blood as the late Queen Mother had in her veins. Camilla descends from King Charles II. Her maternal grandfather was the 3rd Baron Ashcombe; two of her great-great-grandfathers include George Thomas Keppel, 6th Earl of Albemarle and Sir Allan Napier MacNab, 1st Baronet, Prime Minister of Upper Canada 1854-1856. Going back even further, her ancestors include Charles Lennox, 1st Duke of Richmond; Alexander Gordon, 2nd Duke of Gordon; Archibald Campbell, 9th Earl of Argyll.
But I believe it is very narrow thinking to put so much emphasis on bloodlines when discussing how a population today views monarchy.
Yes, for centuries bloodlines were essential when determining a person's rank and position in society. But that was an artificial concept which developed slowly over time with the sole objective of concentrating wealth and power into the hands of very few.
Originally, a leader arose from the masses because he was the strongest, best able to defend the people against outside threats. Power did not automatically descend to offspring; it had to be earned each generation. Eventually monarchies became elected; then such elections were concentrated in members of a single family. From that the concept of automatic hereditary monarchy began to be codified into law, although even over the past 1,000 years there are many, many examples where bloodlines were ignored for other practical reasons.
This whole system worked just fine for centuries, but ONLY because the 90+ % of the population was poorly educated, illiterate, desperately poor, and even enslaved or indentured by laws designed to keep them that way.
None of that applies anymore, and automatic hereditary leadership has been eroding almost continuously for several centuries. In the 16th century most King were autocratic; by 300 years later most power had shifted away from the Crown but only went as far as the nobility. By Word War I that all ended (except for Britain where hereditary Lords still held power). Now even that is gone.
Today, nearly every monarchy is a popular monarchy - it exist only because the people want them to, not for any of the reasons they existed in the past. Monarchs now have to work hard to continually evolve and adapt to serve their people in a way the people want.
I believe Elizabeth II has done an excellent job of that. But had she insisted that her off-spring only marry other people with royal or noble blood, I believe the British Crown would be well on its way to extinction by now.
