I agree that voter apathy is partially to blame here, but I think there is actually a larger issue.
There is potential voting power being distributed via Token House funded grants in the form of liquidity mining, airdrops, etc., but there is nothing in place to capture the new OP holders. In order to claim the airdrop users had to either self-delegate or choose a delegate. As a result, all Airdropped OP that was claimed was delegated and we have our initial delegators/delegated tokens.
However, the number of delegators will really only go down as initial airdrop recipients sell and new holders are not funneled into the delegation portal/claims page. Unless new OP holders or incentive recipients either: A) have already delegated/self-delegated to receive the airdrop (in which case the number of delegators remains the same but votable OP supply increases), or B) take the initiative to go to the claims page to delegate/self-delegate, the number of delegators will be down only.
Additionally, unless current delegators drastically increase their OP holdings to cover the number of votable OP tokens sold by airdrop recipients, the votable OP supply will also be down only.