Norwegian & Monarch will have had an expensive year with fleet renewal and in Norwegians case near 30% growth plans including setting up an Argentinan AOC,HQ refurbishment, introducing the MAX, ETOPS training for 737 crews and a large number of new routes and dream-liners to fly them and their crews.
It is no secret that pilots are leaving Ryanair to Norwegian & Jet2, Monarch will shortly start recruiting more 737 rated f/o's and rumour of DEC will only add to FR shortage.
So I guess by suggesting that these airlines may not last suits his agenda.
Of course given FR cash pile it is within their recourse to address the underlying reason for their own pilot attrition.