An interesting read but ultimately it's more of the ""specialize in a niche"" advice that has been around since it became apparent after Y2K that this market where users replace accounting systems every x years was long gone.
In some respects it's like telling a mechanic to go become a doctor or lawyer. Hell yeah it's more money but it's a multi-year process. Same thing with trying to turn the typical VAR from a generalist (be truthful and admit it's mostly break fix work) to a specialist in an industry.
The problem is you probably can't use the same people and you yourself may not be an industry expert.
TL;DR: This type of advice is great for consultants who advise vars - because it's incredibly difficult to implement and takes many years to do it.