No, not sure how you even got there with Craigslist, and even if AB5 was relevant there's an exception for direct sales that would exempt craiglist and similar sites like ebay.

AB5 doesn't apply outside of the worker classification context, so your rambling about Doordash and food safety regulations is just bizarre. You're right that DoorDash is in the food delivery business and so its delivery drivers would be its employees under AB5 (and thats what the underlying case decided). Door Dash is not in the food preparation business, so restaurant workers wouldn't be treated as DoorDash's workers.

Contrary to your insistence otherwise, running a platform that connects buyers and sellers of something is not the same thing as actually providing that good or service yourself. People say that it takes mental gymnastics to arrive at this conclusion. I see the opposite: how do you manage to convince yourself that people writing code at Uber are in the same line of business as getting behind the wheel of a taxi? How do people convince themselves that a PM at DoorDash works at a restaurant?

I agree that running a platform that connects buyers and sellers in a marketplace is not the same as providing that good/service itself, which is why Amazon Marketplace and eBay don't run afoul of AB5. But UBER/LYFT DOES NOT RUN A MARKETPLACE. They would have to make significant changes to their apps to be considered "marketplaces" by any reasonable or historic definition of the term.

This is akin to saying Expedia is in the airline business.

This is not at all like saying Expedia is in the airline business. Expedia operates like a marketplace. It buys inventory from airlines and hotels and resells them to customers. The ultimate commercial relationship is still between the customer and the airline/hotel. That is not the case with Uber/Lyft as they are currently structured: both the rider and the driver have the commercial relationship with Uber and it only exists through Uber.

And for 3 & 4 this could easily be resolved by having driver set up their own LLCs. But I'm not convinced this is actually a requirement. Plenty of people are contractors and fill out 1099s without operating their own LLC or partnership or some other type of company.

AB5 provides a lot of exemptions, so it's not necessary in every context. Rideshare drivers aren't one of the exemptions.