Yes, which is the goal of any trade - to make money and drive an economy. That's why being part of the collective strengthens your hand; otherwise you're trading in an imbalanced way with other global powers. See what happens when the UK negotiates with the EU on a free trade deal as an example.
As for the second part - i
t has, and is. The difference is these are agreements with those "outside of the club", therefore they don't have the same favourable terms. There's differences in how markets work; such as common vs. single market. That's why the ridiculously over-optimistic outlook for the UK after Brexit makes me laugh - we don't have the clout some people think we do. We're not
small by any means, but on the global stage we are comparatively small next to the trade partners we'll be looking to work with.
So there'll be a hit to us. A substantial one for years to come. It is inevitable.