I used to love Top Gear, back in the day when I was into cars. The problem I have now is that the presenters are the show, not the cars.
The Stig thing. That is all about avoiding the spectre of a 'more expert' view on 'their' show. They limit the expert driver to a non speaking, purely robotic role. They had the chance to dispense with the 'secret' aspect and welcome a new fully fledged pro driver to the team, but they just could not face looking even more silly when they were doing their best to manhandle cars around the track, and appear to have some ability most weekend racers far exceed.
Nothing must subvert the egos of the protagonists.
Unfortunately the time is long past when the work was second to the workers, when a 'star' would have been reminded of their secondary role to the show itself.
None involved will openly question Clarkson's direction, nor seek to unseat him.
Thus the death of the Top Gear franchise will arrive in time, regardless of how it is delayed, as the whole approach is dictated by the past success. There is no room for innovation.
Complacent, flatulent, anachronistic and just a bit irrelevant.
All those ironic jokes about not bothering with ordinary cars that Joe Public might actually be interested in may well come back to haunt those at the helm.