I agree with your general point, like I said above, it's the job of parliament to act in the best interests of its constituents, rather than in their perceived interests (which is an important distinction imo) leaving the EU would be ruinous.
Any competent government would have treated the referendum as the advisory it was, put some proper research in to it, rather than spaffing out article 50 immediately, then come back to the electorate with an honest, "we've looked into this, and it's really brick, are you sure you want to do this?", rather than lying about sunlit uplands and treating the whole thing like a lark.