I suspect the problem is that time is their scarcest resource, not money. They want to spend their time mentoring the startups with the greatest chance of success. Until you reach the point where you have a reasonable chance of success, you're stuck with YC News.
In biotech, I emailed Joerg Poetzsch to ask a question about early stage funding. I got a lengthy response from him. Then, I told him my idea and we've had a wonderful exchange since then -- he ended up writing me a letter of recommendation and said he is interested in selling my product for a percentage of the revenue he generates.
So, if you want basic feedback about your idea, email someone with a blog or website and I promise you can get some feedback. If someone takes 1% of your company for that, you're getting ripped off.
Here's a startup idea Mr PG: I will pay $50 for basic feedback on a very early startup idea and give you 1% equity.
What are the alternatives? Is there any way to get feedback on startup plans from half competent people without broadcasting your ideas all over forums?