You sell investment banking advice, software and self-help books to the Chinese, the Chinese sell you cars and dish washers. What's not self-sustaining about this?
(Of course, the USA still produces lots of stuff you can kick. Don't worry.)
How many Americans are fit for working as investment bankers? OK, you would also need a handful of plumbers, hairdressers and real estate agents to accommodate for the needs of Wall st. Is that it?
Also, where the confidence that Chinese would continue to need American investment advice comes from? If they get the majority of capital and trade along with industrial base, wouldn't these jobs simply follow the money? Americans certainly didn't need any external help back in the day.
America did use lots of foreign help back in the day. The British helped finance the railways. But America did not rely on foreign finance forever. After the First World War there were the greatest creditor nation.
The rise of America has not dented the European standard of living. And neither should the rise of China curb the American living standards. Relative decline is not absolute decline.
(Of course, the USA still produces lots of stuff you can kick. Don't worry.)