It's not altogether certain who and what drives the classes of the TT these days, just as long as the Island is filled to capacity it's ok. And this past decade or so, that may well have been good enough.
Back in the day the Isle of Man TT drove the industry. If a bike was tried and tested on real roads over many laps, then who could ask for a better advert. These days it is more the industry in charge. But as long as the campsites, pubs, B&Bs and restaurants are full it doesn't really matter.
Things will have to radically change with the way the world is going, such as more emphasis on the marmite that is the electric bike, full circuit internet broadcasting etc. Then it may survive.
The Isle of Man's high;y unique position needs to be seen as an opportunity