And you are wrong.
If, for whatever reason, Nathan does not skate the team event - which he may choose not to do given he is carrying an injury - it is a much, much safer choice for Team USA to have Jason skate the short program.
People talk about ceilings and floors. Jason has a narrower range, but the simple fact that is that he is consistent and his SP can easily rack up a mid-90s score immediately makes him a safer choice than someone who maybe can score 100...if the tech calls go his way...or...just not make the free skate. Which in the team event could be 10th place.
There are not many men in the world who can hit 100 to begin with, and all of them are wildly inconsistent. If Jason skated his normal SP and laid down a 90-96 SP, there's every chance he could finish as high as second. In fact, someone on the other forum ran the numbers, and in some scenarios, he could literally win the team event SP - with the not-quite-perfect skates from the GP, let alone if he was perfect!
Vincent is a safer choice for the free skate, where a disaster free would do less damage (as the lowest he could drop is 5th) and a good free skate could assist properly.
Vincent's actually the safer choice for the SP than Jason.
This season from the start of the season to most recent, Zhou has scored 97.35/97.43/99.51.
This season from the start of the season to most recent, Brown has scored 92.39/94.00/89.39.
You say Brown can "easily rack up a mid-90's score". Well the season's results show otherwise.
The main differentiator of course is that Vincent goes for 2 quads to Jason's none. If Vincent does his usual SP, he has greater scoring potential and this greater potential to win or come 2nd in the SP. And before you say it - no, except for certain "fans" of Zhou, nobody cares about 2021 Worlds at this point. It's a new season and Zhou is 4/4 when it comes to short programs.
You say Brown is consistent - well, he consistently hasn't had a successful 3A (with +GOE) in any of his international shorts this season. He had a step out on his 3A at Finlandia, a q on his 3A at Skate Canada, and hand down on his 3A at IdF.
Jason would be 'fine' for the FS where there are only 5 entries, and his PCS advantage will be doubled, so even if he has tech issues he could still beat Messing, the #5 country's entry, and maybe an off-form Kolyada. Even still, Zhou has overall better international results in the FS (186.88, 198.13, 161.18) than Jason (170.13, 165.55, 174.81) by a long shot and has the best international FS score this season other than Chen.
But it won't really matter, as Chen will most likely do one of the segments... probably the SP. And the FS should go to Zhou.
Objectively speaking (i.e. removing one's emotional attachment for Brown or dislike for Zhou from the equation - not that anyone has any!

), Zhou is a better choice for either segment than Brown. Brown is already fortunate that he was selected for the team over Malinin, and is also fortunate to already have an Olympic medal (for a bit underwhelming 4th place/153.67 points team freeskate, mind you - where any skater with a score over 122 in the FS would have received the same result... also worth noting that Jason did even worse in the individual after his team FS, so if we want him to do his best in Beijing maybe it's better that he not do the team).
The 2022 team spots should go to Chen and Zhou.