Well, usually, the trading members should support the faction, sustain their escorts and make the profit to pay the bills. In Vanilla, even the police roamed around in Armored Transports with like 999999999 units of cargo.
Of course that doesn't work all the time. Most faction players either keep their profits for themselves (trading factions like Bowex, USI, ect...) or don't trade at all (Police, Navy). Faction banks are kept full by dedicated members who donate money from their trader chars or faction traders. I don't know which factions (if any) demand members to pay a monthly/weekly 'tax' to their faction bank.
If factions got money from the Admins, players would simply stop donating money to their factions bank since 'its no longer necessary'
It would however, probably be worth a try.
What I do agree with is that corporate escorts should be sustained by the faction, not the player, especially if the respective player doesn't have a transport in said faction.