I'm not actually sure about that. Why would they want to encourage this sort of behaviour when it never made the bank any money? Presumably, C-suite people are compensated based on the financial performance of the bank so they would be motivated to encourage subordinates to commit frauds that drove that performance.
The fake account frauds didn't. The whole reason they were able to get away with it for so long despite the number of accounts is that most of these were no-fee accounts. The people whose identity was stolen to open them never saw a bill or a statement related to the account which is why they never noticed. However that also means that WF didn't actually benefit from the fraud.
The retail level employees and their immediate supervisors were incentivised based on number of opened accounts, regardless of any revenue produced from them, which is why they did this in the first place.