Docker sold its compute infra business.

I wasn't suggesting they buy Docker's (former) compute-infra business but that it would be a good complimentary buy to Microsoft's or one of the other compute-infra player's businesses to own Docker since it is an additional tap into the developer market.

Why bother? They have their own container management infrastructure.

Inbound marketing and developer mind share. Seamless integration between docker tooling and Azure etc etc.

If they did, they would rename it as Microcubes.