Certainly my impression of everything that pg has said is that solo founders have the odds stacked heavily against them when it comes to YC acceptance. I'm surprised that you're surprised that's what we all believe.
Everyone has the odds stacked against them. Successful founders are by definition outliers. If we didn't accept solo founders, we wouldn't bother having them apply.
My group was rejected last time (I'm assuming) because the founders hadn't physically met and because of a lack of prototype.
Now the founders have met (the group of founders has actually received an addition of an elec. eng) but we still don't have a prototype. Hopefully it works out this time around.