"Things like manufacturing and tourism are already booming before Brexit has even happened."
What's pushing those at the moment is that the pound has dropped. The strength of a currency depends on the markets' judgement about the prospects of an economy. So the general view is that the economy will falter once the trade barriers go up. What trade barriers? Those between us and the greater part of our former home market.
We/re not ignoring your "good news", we're simply seeing it for what it is.