It's the same in both cases, it just feels different. Far from attending incidents "they weren't expecting" emergency services have sophisticated data management resources to predict where their activities are likely to peak, and move resources around to cope as best they can. They know fine well that riders of motorbikes, horses, bikes, pedestrians and car drivers will all have accidents on their patch at some point; it's not "if" it's just where and when, and they respond accordingly. Faster in cities, slower in large rural areas.
And the young lads (mainly) who come to grief on the roads of the Dales or Moors are no different to the TT riders fundamentally, they were enjoying doing what they wanted to do, but pushed it too far.
So what you are saying is if I ride my bike in the countryside, even on roads that are notoriously dangerous and I come off and end up in a field I will receive first aid just as quickly as I would at the IoM TT.

I've watched loads of tv programs about the ambulance service including the air ambulance and it always takes time for them to reach the scene of an accident.
The IoM isn't that big and they have Air-Med helicopters based on the island along with various other safety measures. These include GPS tracking (testing this year, mandatory next) and CCTV so they know where the riders are. That is not counting all the fully trained marshals.
If you think that is the same as me lying in a ditch, injured, trying to get my phone out of my leathers as well as trying to remember where I am then I give up.

Have a look at what safety measures are in place for the TT then come back and tell me it's the same as being on the road in the UK. Or even post a link to where there are medical staff dedicated purely to RTCs, as far as I'm aware the Air Ambulances service attend all kinds of emergencies.