Computer games are a completely different problem space. They are a combination of either centrally run by a company with a server (therefore easy to delete accounts which the company arbitrarily deems to be playing 'unfairly') and/or having no monetary value.

On a blockchain, sublinear just means that any scammer can split stake (or just votes) into multiple pieces to instantly increase their rewards. Others will have to pursue this same strategy or eventually be diluted away. The declining curve in the end only affects the most naive or gullible but rich users.