Put another way--the modern financial system was created for a reason. The author supposes that it was a big conspiracy theory to give us all shitty jobs, but in counter I would point out that it has likely never been easier for people to start or grow businesses than it is today.
On the other hand, it's relatively easy for me to ask a bunch of my friends to each lend me $10,000. And, that is more because of the cumulative result of decades and decades of productivity increases in addition to a society that values electronics and computers and the internet. Those factors give these software engineer friends the extra discretionary money to lend to me. It's not because of the magic of the financial system.
The author is saying that there's a huge excess of capital and productivity that could theoretically 'pay' for other types of work. But, instead, we as a society, decide to funnel most of our excess to people who push around accounts ledgers, ruminate on legal logic, generate sales ads, and do other sorts of 'educated' busy work.
I, a rather average middle-aged dude, maintain 4 bank accounts, 6 lines of credit, 4 investment accounts, and 4 lines of insurance [1]. Think of the complexity involved in providing those services to me--now multiply by tens of millions of other people. This does not even get into the financial instruments of businesses and governments, which are far more complex.
The end result of all this complexity is that individuals like your friends can accumulate and access large sums of money to lend to you to start a business. Most new business financing does not come from banks, it comes from individuals, families, or alternate financial businesses like angel funds, venture capital, hedge funds, etc.
[1]
Bank accounts - 2 personal checking - 2 savings
Credit - 1 mortgage - 3 credit cards - 2 check cards
Investments - IRA - 401k - HSA - Brokerage (trading)
Insurance - Home - Auto - Life - Health