Bingley was only 'prioritize', or had most of the attention, when Darcy's unsociable and reserved personality became apparent to everyone. Still, in the end, when Darcy's behavior was recommended and became acceptable, he was again exalted in their eyes, and Bingley was, once again, push to the second rank.
Why?
I think because most people love the mystery behind the 'silent-type' image, the pride (not vanity), and confidence of the person (such as the character of Mr. Darcy), incites challenge and interests. For men, it shows superiority in personality. For women, apart from the countenance, the 'challenge' he incites (and excites) them, doubling with the hope of being 'the one' who would catch the eye, change and warm the heart of this difficult one, makes him interesting, and a great "catch".
People love mysteries and challenges, and the harder these two things are, the more they put their full attention, or focus to these. Mr. Darcy's personality provides more mystery and challenge, than that of Mr. Bingley's, and so he garnered more attention and admiration than his friend.
.. and oh, it was said he's more handsome and rich than Mr. Bingley.
