The biggest single reason against the lab leak is this:
Its really fucking hard to reliably grow human virus. Yes, the Wuhan lab does it, but for like ~10 strains. It takes years of planning, and lots of money. Its not like you can easily hide that kinda shit.
Its not like you can dump the virus into a Petri dish, shove it in a incubator and have done with it. You need hosts and proxies. And guess what? something that replicates well in hosts doesn't replicate in humans. Not only that, there is a strong chance you have to modify the hosts to better accept the virus.
Also, its not like SARS-like virus is rare. MERS is relatively recent. MERS didn't catch on because you are very symptomatic.
Its really fucking hard to reliably grow human virus. Yes, the Wuhan lab does it, but for like ~10 strains. It takes years of planning, and lots of money. Its not like you can easily hide that kinda shit.
Its not like you can dump the virus into a Petri dish, shove it in a incubator and have done with it. You need hosts and proxies. And guess what? something that replicates well in hosts doesn't replicate in humans. Not only that, there is a strong chance you have to modify the hosts to better accept the virus.
Also, its not like SARS-like virus is rare. MERS is relatively recent. MERS didn't catch on because you are very symptomatic.