That's an odd viewpoint from the above poster =o.
I would instead tell you that you'll be happiest playing among people with similar ideals, or dedication. If you're someone who comes prepared and works at studying/reading for the game... then you'll not be very satisfied in a group where people show up spottily and generally bang their heads against a wall with no plan. It's always good to move to a guild more your speed, and you'll get to do fresh progression with them next tier.
A single person does not have the power to change 10 others typically, you are much better off accepting the reality of that and moving on to somewhere else if you feel there's a reason to. It is just a video game, and most of the non-real-life friendships in game fade pretty quickly.... that's just the nature of it. You'll meet new people quickly, and the old ones will fade away quickly. The few people you are actually close friends with are an exception and generally it's easy to stay in touch and do things cross realm.
Also bridges don't usually get burned unless you set fire to them. If you are very gracious when you leave you can often keep good relationships. I still goof off with, do cross-realm things with, and trade information with old raiders who left for other guilds (and I was not very happy about it at the time, but decided to be supportive instead of follow those feelings).
And yeah your sights are not too high if you are deserving from the evidence of logs/records. You're not asking to be carried >.>, rather you are asking not to have to carry others. We're not a communist society in theory.. so have at.