It is easy. Y Combinator's application process is designed to take only an hour or two, though it can take much longer if you have to figure out what your company is going to make at the same time. But you have to figure that out anyway -- it's not really a difficulty of raising seed money.
Y Combinator is very selective, but there are many other incubator / tech accelerator programs where the bar is not so high.
Then again, as pg himself says, the better you are, the less of a "real" reason that you didn't get in. If you're one of the top 100 startups in this cycle, all of which have potential, you might not make it just cause there are another 35 great companies they decide to go with.
Y Combinator is very selective, but there are many other incubator / tech accelerator programs where the bar is not so high.