If you only own bitcoin than your vote is counted far less than if you actively contribute to the ecosystem.
That's absolutely backwards.
The best contribution to Bitcoin is every owner's respective economic share.
Yes, that absolutely implies that large holders are de facto more powerful than those with less coins.
No, your "activity" has nothing to do with this.
TLDR: The investors run Bitcoin
http://nakamotoinstitute.org/mempool/who-controls-bitcoin/What are the implications of this conclusion? The motivation of investors is the value of the coin. The general rule about Bitcoin upgrades, therefore, is that upgrades which increase Bitcoin's value will be adopted and those which do not will not.