Waiting for the Right Opportunity for Requirements Management

Over the last 12-18 months, I've come to fully appreciate the importance of waiting for the right business opportunity to introduce Requirements Management into any development project. The value of requirements elicitation, analysis, and validation/verification is not always immediately obvious to business managers.
I've often been pulled into projects mid-stream to fix problems, and whenever I asked for a Requirements document I often get blank stares (like "what's a requirements document?"). Sometimes there's not even a Project Charter, and it'd take several rounds of emails just to identify all the Stakeholders. No matter that some projects have dragged on for 3-6 months without real progress, all the managers still wonder why they need to stop and rethink what they're doing and why they're doing it. They're all desparate to just "fix the problems," and saw any Requirements Management efforts as unnecessary further delays.
What can an analyst do to improve project performance, when even troubled projects aren't being perceived by management as any argument for Requirements Management? I thought that waiting till problems arose would be all it took to bring Requirements Management into projects, but it hasn't turned out that way. Hmmmm...
I don't think my company's unique in this pattern. Unless a company develops and sells software, it's business managers wouldn't have much exposure to IT Business Analysis, and probably no knowledge of what Requirements Management is in the first place. For my company, the situation is exacerbated by the fact that the IT function has been drastically downsized, leaving a knowledge/skills "vacuum" that pulled me from web/elearning development into business/systems analysis for the Global Campus these last 3-5 years.
Try as I might, my marketing efforts for Requirements Management fell on deaf ears. It wasn't until very recently that I "saw the door open just a crack," after 2 devlopment projects in a row took months instead of weeks to complete, and one executive decided that something should be done and allowed me to spearhead some process improvments. Not exactly appreciation for the value of Requirements Management, but for me I think it'll have to be close enough. :D
For me then, the Right Opportunity turns out to be an explicit request from a business executive to fix ongoing problems, NOT the mere fact that problems arise in projects. The wait's been far longer then I would've preferred, but then again that's probably just my anxiousness to apply new knowledge.
I'll do my best to sell the boss and the team on Requirements Management, even if the only perceived benefit were to minimize communication breakdowns. But...
Is this always the way Requirements Management needs to be introduced to a team, to wait for the leaders to fail before helping them? I wish they had started listening to me before the projects went south! I could've helped save the two projects that failed!! But then again, I realize now I would've been just inflicting help where it's not wanted.
Please Comment! :)