Unless you want to turn the IoM into a communist state, you (or the IoMG) cannot dictate what airlines serve what airport with what type of aircraft with what kind of fares. It really is as simple as that.
Plus the fact that there are hardly any airlines left that could offer the regional-style service you hope for. BACF, for starters, has disposed of its small 50/70 seater fleet that was used to serve the IoM. They are now concentrating on 100 seat E190s. Flybe - gone. Stobart Air - gone. flybmi - gone. Just look at the recent problems finding someone to serve the heavily subsidized Dublin/Donegal route - they had to haul in a Swedish operator as there is literally almost nobody left with 50 seat aircraft in the UK or Ireland other than Loganair and Eastern.