Enron tried this in the late 90s/early 2000s.

That didn't work for a number of reasons (cooking the books), but also network bandwidth is not fungible. Unlike commodities such as oil or natural gas, bandwidth’s value is highly dependent on specific factors like location, time, and network conditions. This variability makes it difficult to standardize bandwidth as a tradable commodity, complicating efforts to create a seamless trading market.

There are a few in the crypto/DePIN space poking at this problem. I remain highly skeptical.

Theoretically would be cool. Basically you have a docker that can run anywhere and you automatically migrate it based on prices between different service providers. The issue is there isn't incentives for the cloud providers to do this, because it wouldn't benefit the incumbents.

Maybe if the government mandated it at some point, like phone number portability was mandated.

That could work for some use cases where you transfer in bulk, like backups, CDN sync, research data transfer, etc. Either auction or off-hours or "spot"/low-QoS.