Re: About Time
Netted out, Efficient Market Hypothesis says that in “zero sum” terms we neither gain nor lose overall.
It's not a zero-sum game, so your assumptions are false. The UK is generally running at a net trade deficit of around £3-4Bn overall, and around £60Bn with the EU, so increased tariffs hurt us more than they benefit us. Tariffs would only benefit us if we ran a consistent trade surplus. Given that the EU would likely be able to get some goods and services elsewhere cheaper if we added WTO tariffs, that deficit would grow, not shrink, under no deal, and that which we have no choice but to import (food) would be more expensive.
You have fallen prey to thinking that the UK is somehow important and indispensible to the rest of the world. This hasn't been the case for a good part of a century, not least due to our appalling history of how we have treated people from other parts of the world in the past. (There's little that is glorious about the history of the British Empire).