Scientists at the Wuhan institute of virology were doing gain of function research on SARS since at least 2015, making a chimeric virus which could infect mice:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4797993/
The paper reads:
"Using the SARS-CoV reverse genetics system, we generated and characterized a chimeric virus expressing the spike of bat coronavirus SHC014 in a mouse-adapted SARS-CoV backbone"
The market where Covid-19 was first spotted is a mere 30 minutes drive away from the lab. If a new virus in America showed up 30 minutes away from the CDC's virology lab, you'd be similarly suspicious.
I'm not sure there's clear proof that it is a lab leak, but it's not obvious to me that it isn't.
Lab leaks have happened at other times in history:
You asked:
"Why would you spend millions of dollars and months of work to have a team of scientists create something that you could just go to a cave and get from a bat?"
The answer there would be that you can't just go to a cave and get it. No one knows where the natural reservoir is, no one can point to a cave which has covid-19, or a population of bats or pangolins that have it. If they could find those, we would know for sure where it came from.
Why would people have been doing the research? Could be a weapons thing. But more likely, I'd think it was to study coronaviruses with the hope of avoiding future pandemics.
