It sends a message that getting into YC is way to important to miss and if you don't get accepted you stand little chance of getting anywhere on the startup scene. Or in life.
I can't imagine this is the spirit that PG and now Sam Altman are interested in portraying.
YC came about in 2005. There were companies that were formed prior to that that have been hugely successful. And there have been companies formed after that that have been successful. Not to mention a whole lot of lifestyle businesses. There are also many other incubators, mentors, investors, angels etc.
I think it's really dangerous to get all worked up as if not getting into YC is pivotal in a non correctable way.
That said I understand the anxiety. But I don't think things like this really help because they reinforce the implied importance more than anything else.