It's not a single pilot. It's the go to way to influence a system so that's what people do.
Ever go to areas during "events" (lugh, sorbargo etc)? I went to them all and saw systems being influenced and it was still a lonely place. People do what works and this is currently how it's done.
If you are not seeing anyone, or else seeing too few players, there is a good chance you have some issue with the matchmaking. Perhaps there are too few players close to you in the real world (i.e., with whom you would have a low ping), or there is some issue with your router or firewall configuration, or your net connection has some other issue that the matchmaking algorithm sees as degrading the experience for everyone else. Those issues can reduce the number of players you see, or even block them completely, while still allowing you to play.
Anyway, if ten pilots trading in solo are having ten times more influence than a single pilot in open, it's working as intended, and to change it would be unfair to the solo players. If a single pilot trading in solo is having ten times more influence than a single pilot in open, then there is a bug that must be fixed. Only frontier can see specific influence numbers (and the number of players in solo and private groups), so only Frontier can tell if there is an issue.
The problem with this is they undermined their own major mechanics.
They undermine what you see as the game's major mechanics. It's not something all players agree, and it doesn't seem to be something Frontier agrees.
You seem to think that denial — as in, preventing another player from doing something he wants so you, or your faction, can get an advantage — is an important mechanic, and that everyone should be subject to it. To be fair, it's a common point of view in the hardcore open world PvP crowd, so you certainly aren't alone. But Frontier went in a different direction.
You see, a peer to peer architecture allows for less laggy connections and much lower operational costs, but it does have some disadvantages, such as making it impossible to force specific players to meet each other. So, denial as a tactic would never work on a global scale anyway. To avoid issues with this, Frontier went for a different system, one where denial can still be used, and effective, on a local scale — it can be a lot of fun if everyone involved is playing that game, after all — but where what truly determines the result is aggregate effort instead.