political disengagement

Bar one or two exceptions, Prime Minister's Questions is exactly the same every week. It is not that it never deals with the serious issues of the day - it does, it is just when these occasional days occur, the result is a solemn affair that journalists and MPs agree is disappointing. Indeed, such a PMQs only really occurs when there is no other choice remaining.
During Thatcher's reign, few would have uttered the now-commonplace anti-political statement: "They're all the same as each other, so why should I vote for anyone". She gave people a reason to vote, one way or the other.
While there are good reasons for liberal populists to be disillusioned, the solution is not to abandon representative democracy but to reinforce it. The liberal populism of Grillo and his ilk must be confronted before it's too late.