Aside from the Max challenges and uncertainty, he's admitting this week that there are markets under huge strain, I.e. Frankfurt.
Lufthansa have not taken Ryanair's entry to Frankfurt likely. The message is clear Ryanair will only invest into unprofitable routes for a limited period of time, by which time the incumbent throws in the towel and Ryanair gets all of the business. Lufthansa and easyJet since Carolyn McCall's departure have shown that you play the long game and challenge Ryanair instead of giving up on your market. Frankfurt is an example, as is Belfast in the case of easyJet.
I'm not entirely convinced that Ryanair have the lowest cost base in Europe of the LCCs, I think in unit cost Wizz would be ahead and a few LCCs comparacble.
We see at many UK bases where Ryanair and easyJet battle it out, that easyJet is larger in , flights and based aircraft numbers.... says a lot.
ei-bud