For the next ten years, and probably more, Britain's economy is going to be all over the place. It will be hard to keep things stable whilst new treaties are negotiated and new trade links are established.
Britain is effectively rebooting its relationship with it's biggest trading partner. There is no way that such a move cannot have significant negative repercussions.
I've already seen such repercussions with UK friends who run small businesses being impacted the drop in the value of sterling. Another UK friend who runs a tourist coach business has been told by his EU based tour operator clients that once the Brexit happens they may have to drop him as a supplier - which now means a planned expansion has been put on hold. This is the sort of stuff happening even before article 50 is invoked, once that happens then all bets are off.
The leave camp didn't have a plan, but even if they did there would still be major negative effects on the UK. And so far people have only focused on issues surrounding trade the movement of people. There are dozens of other issues that will need to be dealt with as well such as standards compliance, product safety certifications, cross border consumer issues, science/R&D partnerships, the NI peace process, OpenSkies agreements and so on and so on.
Lets assume the author is correct in his thinking and that in 10-20 years the UK economy will be thriving, you can't deny it will have been a very, very painful journey to get there.