Some of them of course are invented whole cloth. British Received Pronunciation was invented and needs to be learned and is the standard of the upper class. It's neither right nor wrong but it's there to differentiate.
replyYou say “needs to be learned” but that’s no more so than any other accent.
replyWe just grow up with it because it’s how our parents and the parents of our friends speak.
If you want to change your accent you can, of course, get elocution lessons but most Brits do not. We just have a large variety of accents of which RP is one.
"Received Pronunciation was invented"
replyHow so?
That's the thing with standards: there are so many of them to choose from.
replyYou don't have to follow them, but you do you should be ready to accept the consequences of your choice.