Sorry, but the reason some have become megachurches is that they have followed certain principles -- principles straight out of Harvard business school -- on how to "succeed" as an organization. The scandal of the megachurch movement is that it is possible to become big, without the necessity of following the Holy Spirit.
Many of the Megachurches do not apply Harvard Business Principles, but simply apply good management, or good stewardship.
Others succeed despite themselves.
You're trying to paint with too broad a brush. Megachurches are not at all from the same mold. Mine is very tight doctrine:
Beginning sentence from a sermon two weeks ago:
"The trouble with most marriages is..........the husband".
He asked the husbands to stand, which we did, and said "This sermon is for you. For some of you this is the last time we will see you here".
And then he laid into us.