The oracle is not monolithic for information-optimization reasons. Rather, it's monolithic because there's a single project that has funds that it's willing to give out in retroactive grants, and so _some_ mechanism must decide where those funds go.

(This is perhaps what's not clear to readers from outside the crypto space: all of these discussions are assuming that this is being implemented by some project that has network effects and can extract fees that are necessary anyway for congestion-control reasons, where the only remaining question is where those funds go)