A neat idea from the gamebook Battlepits of Krarth (Dave Morris, Oliver Johnson) is to make you start the adventure while choosing a sponsor as the first obligatory step before entering said battlepits. In pure gamebook fashion you can choose blindly and then of course you risk getting a bad one (one sponsor is actually a vampire who, guess what, is more interested in getting your blood than having champions to compete), or, you know, you could try to get some information first and make a better choice…

Of course, a Choose Your Own Adventure has a limited scope and so there’s only three sponsors to choose from (others are mentionned but aren’t availaible). One good, one bad and one really bad (the aforementionned vampire). An interesting twist is that the good one, Magus Balthazar, is harder to get, he’s actually picky as to whom he chooses. It’s not like he wants the first boneheads to cross his door to represent him in this prestigious, yearly competion. No, no, no. You will be tested, and if your intelligence is found lacking, well… You’ll have to find another sponsor.

With a Tabletop RPG, of course, you could have a lot more options to choose from, leading to interesting roleplaying opportunities.
But what’s the point of having a sponsor? Well, suppose you get one that’s interested in your prolonged well-being, a sponsor could ensure that your chances of success are a bit better, providing you with starting funds, equipment, henchmen and so on… And, depending on the style of play, maybe a kind of insurance against setbacks (healing services, or even resurrection).
In any case, there would have to be something to gain for the sponsor too. A share of the profits, first bid on precious stuff, etc. In a TTRPG, a sponsor wouldn’t be a simple employer, there’s a long-term relationship (or debt serving) to consider.
If I ever do something like a megadungeon campaign, you can be sure there’ll be sponsors around!