Miners do make Bitcoin rules though, the entire protocol is a consensus protocol driven by the miners.
This process is how all changes to Bitcoin get rolled out.
> By 8 August, another milestone was reached when 100% of the bitcoin mining pools signaled support
The majority of miners implementing new rules only has an effect on which rules the validating nodes will start enforcing if those nodes implemented them and allowed miners to signal when to start.
A big miner has the same voting power as you with the client running on an RPi.