"RP", by the definition it was originally given, doesn't really exist any more in anyone under 70 or so. What you may now think of as "RP" is usually called Standard Southern British, or SSB.

You just need to listen to the various generations of the royal family to see that RP is effectively dead.

I read somewhere that accents “move” up the social hierarchy over time. Aspects of speech which are widely working class will eventually become traits of the upper class - while meanwhile the working cm lass have moved on.