I agree with you, I believe some agents just don't get it, especially when Trulia doesn't require payment to fill out a good bio (most sites don't). Now, if an agent is just more old school, that's not bad either, but you'll have to reach out in more traditional ways. You could always seek out listing agents like you did here, by writing to agents there, like you did here. You'll probably be inundated with no-thought-involved "I'm the best agent, call me" responses, to much more thought out responses. At least it'll be a start.
From having read agent responses to questions like "Is paying for Pro worth it?" or "How many deals have you closed because of your Trulia profile?' the overwhelming sentiment is 'Well, it might work...some day."
Folks must choose where they will spend their precious time. For many, committing the real energy and time to make social media work pays fewer dividends than actually meeting flesh and blood home owners and buyers. These agents may have reviewed all the look alike profiles on Trulia and didn't want to look alike.
It's not fear, nor is it laziness, it's a choice made on an individual basis reflecting their expectation. One may say it is self-fulfilling. Just as that is a choice you expressed not to use someone who did not take the time to etablish a connection with the audience, others have stated they would not do business with anyone who did not use REALTOR(r) properly. Isn't it the choices we make that makes this world a more interesting place?
I would be looking at their listing count as a better indicator of their success, not their profile.
What activity does create the greatest consumer response on Trulia?
Like it was said, would you contact someone whose profile was bland, generic, or incomplete? Just ask yourself that question.