That's called a hype train, it was the same at the PS2 launch (as a Dreamcast owner I got so upset I never bought a PS2, during that "generation" I had a Gamecube and an og xbox!)...
Eventually the PS2 got the games people expected on it, it even dominated so much that there were tons of exclusives, despite Sony's refusal to pay for them!
it was the same for the PS3, it took a while for it to have a good library...
Now, I would not say the PS4 has a bad library, it has a steady flow of good games coming, the free PS+ title every month and the best console versions for all multi-platform titles... which in and of itself is an argument to buy a new console (I know more people who want PS4s just to get 1080p CoD than anything else for some reason... I don't even play CoD).
Obviously a lot of people prefer to wait until there is a critical mass of titles to get a new machine, it's very rational, but without the early adopters you would all be stuck on the original NES or something, because no console ever launched with a complete library from the get go (this is also why windows PCs are so hard to detrone as the main computing platform, despite the fact that OS X and arguably Linux both offer better desktop experiences, they don't have the same software library, maybe replacements, but not the programs 85% of people are used to...).