There's the problem.
If the clubs can't manage and the whole thing falls flat what happens then. Back to the status quo for the clubs. They won't mind - they gave it a shot.
The FA can't look at it that way - if it is not done properly they will have cruelled the pitch for another couple of decades.
We don't know how the fa look at it due to the secrecy of the process and there seems to be divergent opinions from individuals in the organisation as far as I can tell
having said that, the position you suggested doesn't make sense to me
you say that the downside to removing criteria and letting clubs decide is clubs could find out in sufficient numbers that they can't sustain being in the league and leave which leads to insufficient teams to have a league.
Well, then you find out that we can't have a viable second tier regardless of how much you lower the standards. Perhaps that makes clubs shy to try again until the pitch is "uncrueled" after "a couple of decades". But in this thought experiment they shouldn't want to do it for a few years anyway because they just found out they financially can't manage the extra expenses.
higher criteria means higher expenses. This might result in revenue increases being large enough to compensate, or it might not. Ultimately it is a risk and
increases the risk of the competition even if the competition eventually goes ahead. It also means the clubs business environment is even more different to the one they have gotten used to so it is a bigger adjustment. This also adds to the risk. True, higher risk could mean higher reward but it is a higher risk.
But all that aside, if the downside of giving clubs more say over what criteria a nst should have is not having an nst for 2 decades because the pitch is crueled after a hypothetical collapse, well we are already almost halfway to not having a second division for 2 decades