Those who can - do.
Those who can't - teach.
Those who can't teach - become critics, usually 'pretending more than anything else' to actually know what they're talking about, so as to justify their condescending & often completely inaccurate comments & statements.
Those who can't do any of the above - get quickly recruited & hired by governments everywhere - who are then overpaid & underworked, receive countless bonuses, benefits and other massive expense accounts and cash payouts over the years, only to end up with entirely undeserved ultra-healthy retirement packages.
Pardon the partial rant - I guess I'm just sayin' too...