Because the notion that they would suddenly decide to fix it at 4pm and play the whole embarrassing episode out in front of the entire world is completely absurd.
To those who are seriously suggesting that they kept drawing the balls until they got what they wanted, why didn't they start the process at 1pm in the afternoon rather than draw attention to it?
Also, even in the event someone at carabao/the EFL inexplicably felt the need to fix a round of reserve team fixtures in a trophy 99.9% of people give zero shits about, do you seriously think an organisation the size of Twitter would allow themselves to be thrown under the bus in the process?
The risk involved and the number of people required to be complicit simply don't outweigh whatever you think the end game is here.
Twitter has been left looking like a laughing stock in all of this and at a time where social media companies are looking to move into sports broadcasting there is no way they'd take the fall.
City drawn against a premier league side? So fucking what? there was 6/7 chance of that happening and we ended up with one of the poorest teams left in it.