Bournemouth catchment is only big enough to support lots of routes when the economy is booming. When people are watching their budgets, as now, it's the first place to suffer, especially in winter. On top of that, marketing is done from east mids etc. However, does anyone seriously think that MAG would spend £45 million and then not try and get airlines in? Who knows what Ryanairs' real reasons are - they've never had problems with their most popular routes in the winter before so there's maybe a political element to 'pulling out' for 3 months.
Anyway, the place will not be 'mothballed' etc - there are many other flying organisations operating. Passenger numbers down - yes dramatically - aircraft movement numbers down - only a few per cent.