The other issue is that many businesses can claim back the VAT along the way, meaning the cost increase happens at the point where the consumer opens her purse, not every step along the way.
As for unfairly impacting the poor: there are ways to allow for that- e.g. the UK government exempted many sorts of food and kids' stuff.
And as for the specter of gradually raising VAT as one of the experts proposed: the opposite seems more true recently. E.g. the UK government reduced VAT to assist the economy to weather the current crisis.
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1
