We will be great again. We have some of the best engineers in the world but don't convert it into exports abroad e.g. the car industry.
Most of the things that are going to go up in price are either unnecessary or subsitutional. It's a chance to reevaluate our epicurean tendencies and think about what is important in life. Is it so important that we need to buy a new BMW at x price? Is Nando's chicken on a different plane to other chicken, or have we been sucked in by the clever marketing of international companies?
Leaving the EU is not going to be a pivotal point of societal revolution where we all come to the sudden realisation that we're actually self-sufficient and the best at making and doing everything ever.
People will still want BMWs and Nando's and iPhones and whatever else they spend their money on, and realistically the prospect of not being able to immediately afford those luxuries often isn't a barrier anyway.