The most interesting question for me is what do we do if, as seems likely, automation and technological development produces an abundance of goods and leisure time.

Anything abundant, such as air, we will use freely as we do now. Anything scarce, such as front row seats to a live concert, we will either distribute using an economy as we do now, or we will distribute with central planning, because that works a lot better when you have a superintelligent AI as the planner.

Also, I'm skeptical of it it so most stuff is abundant. We will simply increase the population until it's scarce again.

If this future comes about, how should we structure our economy and society?

We can just use simple wealth redistribution. Tax everyone X%, and evenly distribute the money. I would not recommend communism unless you have a superhuman AI central planner.