I don't really think this shows an existential crisis for the centre-right (unless the abstaining youth suddenly start voting in the future, which is a possibility). In France, Spain and Anglosaxon countries the main conservative party does terrible with young voters, but in France and Spain they are being replaced by liberal parties with a relatively young voter base that are becoming more rightist by the day (LREM, C's). I think the continental European centre-right isn't in a lot of trouble at this moment, but the Anglosaxon right seems to be in an extremely dire situation.
Agreed