1. Those features aren't a la carte, so the share matters if you're not utilizing those extra services. You're basically paying for the audience.

2. Valve does have tiered shares, but it's based on publisher sales. And it's extremely high. I have to check again, but I believe the threshold was 25m yearly revenue for 25% and 50m for 20%.

Innsome ways it's more frustrating. It's basically a tax cut for the rich.