Well, actually, if we are talking in terms of Ryanair, they have left an airport Ryanair have also left in as many words.
Yet they have become ever the more cosy at EMA, one of Ryanair's biggest bases in the UK. So really, WW is more saying 'hello' than 'goodbye.'
But for the sake of Manchester, yes. ZB, LS, U2 and the IT crowd have the market covered from MAN for the foreseeable future.