What is it about (many) people on the left that predisposes them to loathe the wealthy? I mean, who do they think pays them? Who do they think employs them? Jobs don't just materialise out of thin air.
Sir Jim Ratcliffe has left the UK (dare I mention he lived in Switzerland for six years 2010-16 anyway, so this isn't exactly jumping ship) - but most haven't, and, yes, we'll manage without him. As much as many on the left might want British civil society to collapse post-Brexit in their deluded masochist fantasies, it isn't going to happen - and once we've left the EU and the dust has settled, the same people will be employing them, paying their wages and putting food on their tables.
I'd hazard a guess that most people decrying Ratcliffle for moving to Monaco are likely also ardently pro-Corbyn, if not otherwise ardent Labour voters, and if they think that Brexit is causing a mass exodus of the wealthy from this country (which it isn't, by the way), then I'm afraid a Corbyn premiership would cause far worse.