There will always be several levels of folks who act as "expediters" in business transactions. That won't change. There will always be groups of people who match people with services. That won't change. So, yes positioning himself to feed off the free money food chain. That will trim down but won't go away.
As for a skill set that doesn't make anything? Well, there are plenty of skills that don't make things that are still necessary in any economy. It's not that we need to remove them from the economy, it's that we need to rebuild the manufacturing industries. That is where the problem is. There is both an market for and a need for both skillsets and both industries.
And you are dead on that we cannot be a 100% service industry country. Even with reduced lifestyle expectations we will fail at that.
I guess I was referring to a broader definition of manufacturing jobs e.g. including mechanics, plumbers , doctors .., intellectual workers , actor/actresses, anyone who engages in producing or sustaining a product.
On the other hand, the "expediters" exist because of the inefficiency of the marketplace. Once some company like Amazon, Costco, ebay, carmax(?) figures out a way to cut them out , these jobs have no reason to exist. The same can't be said of the "manufacturing" jobs as long as the products remain relevant in the marketplace.