Viruses don't develop naturally anymore. They haven't for many decades now.
With modern medical facilities in place, labs know about and predict natural virus development years in advance, and prepare vaccines before hand. Any virus that developed this quickly was man made. It's part of the virologist meta contention. Labs predict the next evolution in viruses and prepare. Labs know that other labs are doing this. They try to develop virus weapons that will work around the coming vaccines. Labs in other countries know this, and attempt to predict the meta, and prepare for it. If they get it right, you don't notice a thing. If they don't, the world economy collapses. This isn't the first viral chinese attack, but it is the most effective thus far. There will be more.
It doesn't help that corporations know about this, and try to monetize it.
Sorry, but this is a load of bollocks.
Labs cannot "predict" natural virus development in the way you make out. They can identify potential mutations which could cause viruses to become more problematic, but there is no guarantee. They can store the genetic codes of various virus mutations, from which vaccines may rapidly be developed. However, the benefits of this are nothing like what you suggest. Trying to develop a vaccine to a laboratory experiment is in large part a waste of resources, because there is no guarantee the virus that eventually emerges will be sufficiently similar for the vaccine to be effective. At best, it might help guide some vaccine optimisation. When a new disease appears, and as happened with SARS-CoV-2, the genetic code of the virus (as was infecting the human populace now) was quickly revealed and published, and all the vaccines were developed from it. Why use a worse equivalent from an experimental prediction when the real thing is right there?
The delay in vaccine production is safety and efficacy testing. There is no point preparing vaccines to theoretical lab-developed variants, because they could not reasonably be tested. We would need to create thousands and thousands of vaccines to cover all the possibilities generated in labs, and running these through trials would be exorbitantly expensive (and pointless, see above), never mind all but impossible given we have no way of testing the efficacy of a vaccine against a virus that no-one catches.
If this came from a Chinese lab for which China had already prepared vaccines, why didn't China have a vaccine ready? Several Western companies had vaccines ready and tested before China did, and China's vaccine was significantly less effective (in fact, it only just squeaked past minimal standards for approval by the narrowest of margin). Bluntly, Russia - probably less technologically advanced than China in biotech - developed a better vaccine from a standing start in the same timeframe. So there is a fundamental inconsistency in claiming SARS-CoV-2 came from a lab, and that these lab experiments facilitate advanced vaccine development in the way you say.
Finally, no sane country prepares a biological weapon of this sort. As we have seen with Covid-19, such viruses wreak havoc globally: it poses a vast risk to one's own country. The modern "gain of function" experiment is very new, it has not been going on for decades. Any viruses pre-~2010 would need to be artificially manipulated in ways that would be obvious from their genetic code, and no-one has found such a virus doing the rounds. Where there have been lab leaks, they are of "old" viruses - variants from the past that have been stored for analysis, not new and altered ones.
A quick look through history tells us these sorts of pandemics keep occurring. Again, there are a lot of viruses out there in humans, in animals, mutating and evolving all the time. Many of these are a few mutations away from being transmissable to humans, and of those inevitably some will eventually develop the potential for a Covid-19 level of infectiousness. Every unit time, nature rolls a million billion-sided dice. Every once in a while, it rolls a 1 and we have a new major health concern. That's just the way it is.