Our capacity to impact the backstory remains the same as ever, I believe. The Live events allow for a significant particiaption of players with ongoing storyline arcs, vis-a-vis actor interactions and completion of various objectives, making a lasting, prime fiction, impact.
The faction war arcs are largely tied up, with the Blind Auction being undone by the liberation of Placid/Verge/Essence, which I'm proud Moira took a part of back in the day. There wasn't much more going on in the Amarr/Minmatar front, however, occupying a star system on behalf of a faction is still most certainly a significant impact on the backstory of the game.
I think it is rather presumptuous for us to believe our capsuleers capable of doing, or undoing, thousands of years of human history just over the course of a few days of typing things in the IGS. That is where the lack of perspective lies, I believe. Even with the contiuous efforts of years of certain RP alliances, there is still a long way to go scratch the surface of the storyline in 'real time', meaning, human epochal history.
The impact of any one person, over such period of time, can be said to be vanishingly small. However, things like faction war, live events, and others, do bring to mind that accomplishments of skill, teamwork, and perseverance will be rewarded by CCP. Acts of a lone wolf attempting to hog the headlines, probably won't.