The monarchy was hereditary for a long period before Henry VIII. Yes, fights would break out, but back in Norman days, and from then on, eldest son was the rule.
I'm part Polish, & up until our disastrous last king Stanislaw Poniatowski in the 18th century, we had a system where the king was chosen from the nobles each time. The issue was this was vulnerable to outside pressure. Eventually Catherine the Great removed her ex-boyfriend's throne & helped partition Poland in the 1790s.
So the hereditary system is grim now, but it did have some benefits in the past as well as drawbacks