Having just watched it and I although enjoyed it,I felt that the show has become tired and formulaic.
Most TV shoes of this age have had a revamp to avoid this but Clarkson and co are of the opinion that as long as folk keep watching it,then they'll stick to that formula.
It's also a case of the persona taking over the real person.They've become accustomed to acting in such a way,that I think they've become like that in life as well.
TG and Jereny Clarkson in particular,are getting publicity for all the wrong reasons nowadays and I think the writing is on the wall for the show in it's current format,even if it is a huge money maker for the Beeb.