The "mega church" is hardly anything new.
More than 2,000 a week? There's probably a fair number of Catholic parishes in the US that get that number. I guess there's no need for them to gather 16,000 at a time like Osteen's church, you're gonna hear the same Scripture readings at every parish on Sunday.
The question I have regarding megachurches is not how many they get for Sunday services, but how many are present on the church grounds more than twice a week. A megachurch can offer a much wider variety of ministries and spiritual opportunites than an ordinary church. Megachurches have schools (including middle and high schools), bookstores, active youth programs, young adult ministries, a wide variety of music and art opportunities, support ministries, etc. etc. It's truly amazing how these places function.