I heard a rumour the Manx govt. pays some subsidy for new route.
They almost certainly do. Whenever a new route is launched from any airport, it almost always receives some sort of support from either the government or local council.
This often takes the form of joint advertising campaigns, or a direct subsidy such as the Scottish Route Development Fund, paid either to the airline or the airport to reduce landing fees. Other forms of support and incentives will also be offered to attract new routes.