The venn diagram of contract workers is not a perfect overlap with "gig" work. Just because you're self-employed, selling your services to others on a contract basis, doesn't make that gig work.
doesn't it? as far as i can tell, the only distinction between "gig economy" and contract workers is that contract workers actually get paid at rates that make it sustainable and that being between contracts isn't a catastrophe, whereas jobs classed as "gig economy" pay low enough to keep the workers desperate for the next gig.
Contractors also have more flexibility to develop a relationship with the “client” for better opportunties down the road without the middleman/platform interfering.
That's quite different to say a session musician getting the call can you by at Abby Road tomorrow at 9 "big name star" needs a guitar player.
Gig in the original sense originally a musicians term for a Job