Grumman saw that it wasn't going to be produced and it was likely the Government had quit paying for testing. The weight issues kind of make me laugh "your 10,900 pound plane weighs too much so we are going to buy a couple of 12,000 pound airplanes instead (Hellcat and Corsair) Same size wing as a Corsair, 303 square feetWithout knowing the actual VMC of the aircraft or how its weight issues were going to be solved along with other problems Grumman didn't want to mess with, it's kind of hard to call the F5F the be all end all of naval fighters in 1941.
Even Grumman was trying to wash their hands of the project by the end of March 1942 with a memo to BuAer stating they had no further interest in the F5F.