This article is (yet another) attemp to romanticize and put to pedestal 'startup with a novel idea'. It is worth to mention that trying to trick/persuade/convince (choose freely) thousands (literaly) of people to go this path, benefits tremendously ycombinator - not the persuaded founders. Because for YC if only few are (hugely) successfull they win. Not so for the other thousands. The fact that few means 200 here, does not change that 'other' means around dozens of thousands.
Startups with 'right but not novel' are also GOOD. But they are muuuuch worse for YC. YC is not seeking all investments to end with modest returns. YC is seeking few, but with HUGE returns.
Pay attention also, that ycombinator itself is in the 'right, but not inventive' camp. It's like 'selling investing advices', while in the same time, author makes money on sth completly different (advices :). BAD ADVICES, to be exact.
p.s. I'm also tired on romanticizing airbnb in literally 3 paragraph (search for airbeds if you missed it). This is a pattern.