I went through that idea on the PS4 about picking up the system for one game, which is FFXIV.
My problem comes down to overall cost versus final objective.
Would I get a PS4 for Bloodborne, probably not. I find that other games I tend to play outside of FFXIV fall flat where I tend to stop playing at some point (usually it's not even when the game gets tough) and then just don't pick it back up.
I just feel that I can wait for the PS4 to drop closer to the $300 range and by then, see where they place HDD space needed and hopefully start a library of games where I could get a few games in the $30 each.
I've had a PS4 since about a month after it launched. I also got 3 years of PlayStation Plus. In addition to the few physical games I own (Dragon Age Inquisition, MURDEREDL Soul Supsect, Bound By Flame, Thief, AC4:BF, and Lords of the Fallen), I have plenty of digital games to play, thanks to PS+. The PS4 is one of my most used consoles right now, next to my N3DS and PC.