Is there actually any suggestion that Ryanair or Thomson might think about moving from Luton?
Ryanair have maintained a small but solid base of 4 planes for a long time now. The routes must be profitable or they wouldn't continue and of course next year, flights to Copenhagen will join the existing routes.
Thomson similarly have maintained a small 3 aircraft base which whilst much smaller than some other bases is still bigger than many. I dont see why Thomson might consider leaving Luton. If anything, there's surely more of a case for them to grow at Luton than to decline or disappear.