Worm bitten
I think you will find that the ADV has a lot less than 30yrs service, if the Frightning was chopped in '88, that makes around 18 years maximum for the ADV.
And please remember that the ADV is not a fighter, unlike the SHAR, it is a long range standoff missile carrying platform.
Now as for its replacement, as long as it flies very fast, and is very agile, who cares if it can actually shoot down anything.
The basic design of an RAF fighter is fun first, fun second and fun third.