The idea that the economy is based on "consumption" depends on how you define "consumption".

If you think of "consumption" as "buying real world products from Wal Mart or Amazon" then that is wrong, the US economy is not really based on that.

Most GDP in the US comes from the service sector. And one thing is true about human nature - a lot of people like having other people serve them.

There are many things that machines can do for us but we still pay people to do them for us. For example, machines in a food plant can cook pasta and pack that pasta into a frozen dinner that you could eat at home. But people still like going out for a pasta dinner

So even if AI is going to replace a whole lot of jobs, you would still have some people paying others to serve them just because people like having other people serve them.