Over my years of editing Wikipedia off and on, I've come to think this is mostly a bad excuse. The issue is that very few articles meet Wikipedia's real standards for citations. Yet new content provided by experts is often challenged for lacking citations, perhaps because of a sort of status quo bias.
What needs to happen is that there should be collaboration between Wikipedia insiders who know the Wikipedia system and subject matter experts who have valuable information to add.
Worse, the demand for citations is often just absurd. There's a big difference between "this is a controversial claim that might need citations" and "no one has yet bothered to look in a basic textbook for citations."
There are real reasons why experts can't just come in and say "do it my way" but the response has to be geared towards saying "how do we take advantage of your knowledge without forcing you to learn arcane policies?"
Update: As for identifying experts, that's not altogether obvious. But if an article is an absolute mess, there should be a low bar for cleanup. If the article is in decent shape, then presumably someone is running around with a bit of subject matter knowledge, and can coordinate. Think about any area you know something about: how quickly can you distinguish someone who generally is on target from someone who doesn't have a clue?