In that case you influence transaction activity of others to be in accordance to the protocol rules of your node. Your node technically enables you to do that. But in the end, your power to influence others comes from your economic potential, not your node. It doesn't matter if you have 1 or 1000 nodes. Theoretically, you can do this even without node, in which case you cannot completely verify the settlement of the transaction yourself, but you could still exert your influence. Or in other words, your node has zero influence if you don' t connect any economic activity to it.

You can be Elon Musk and yet without a node you won't achieve shit. Of course having more than one only gives you increased service availability but doesn't affect the network. And if your economic activity is not linked to your node it also has no effect.