BE's activity at DSA is not representative of the airlines mainline operations.
I would suspect their presence at DSA is costing Peel and that BE are hapy to last out the agreed term with reasonable yield on the Sun Routes. CDG & AMS will not get the customer support that BE see at its other bases where the same routes are offered with the flexibility of 3x daily flights - even HUY & DTV can even sustain 3x Daily AMS where KLM have made that commitment.
Sad for DSA at the end of the year if BE leave, but it will be the airport that will be seen to have failed rather than the airline not offering sustainable route frequency.