Why are global scientists claiming now that covid-19 virus is not man-made?

https://www.caixinglobal.com/2020-02-25/new-paper-adds-support-to-covid-19s-natural-origins-101520278.html

The global scientists could have come out much earlier to state their consensus claim that covid-19 virus was not man-made but they didn't.  They only came out to state this claim when there were more prima facie pieces of evidence that pinpointed the US as the origin (See my post below).

http://sg-stock.blogspot.com/2020/03/japan-and-russia-alleged-that-covid-19.html

I believe the mounting pieces of evidence and Russian's allegation that CIA created covid-19 virus prompt the US to use its resources to embark on this scientific claim.

We all know the potency of the 3rd generation covid-19 virus in China from its death toll.  The normal virus evolution path is that the earlier generation is much more potent than the latest generation.  Please look at my comment for the post below to understand more about a virus evolution.

http://sg-stock.blogspot.com/2020/02/the-infected-chinese-are-dropping-dead.html

Since the US has 1st, 2nd and 4th-generation covid-19 cases, its death toll should be much higher than China's.  This might explain the high flu death toll (Dec 2019 to Feb 2020) in the US as the flu deaths were classified wrongly since the doctors had not encountered this virus before.

This might also explain the heavy sell-off in the US stock markets last week because the smart investors knew that the covid-19 virus originated in the US and this would hurt the US severely economically and politically.