Wikipedia's primary purpose is not to bring in cash, it's a non-profit, so the money is going towards mission-related activities and supporting the site. Generally, the current level is enough to support the site (check also [1] which is meant to ensure at least basic level of support more or less forever). If donations dry up (which they don't seem to be) the activities may be reduced, but "bringing in a lot of cash" by itself is not really the purpose, the cash is the means to get things done. It's a bit different for for-profit establishments when usually getting profit on the investment is at least one of the goals of the whole deal.

[1] https://meta.wikimedia.org/wiki/Wikimedia_Endowment