No you didn't

. But not much they can do about it when the hardware doesn't support it. I mean it likely will support PSMinis and PS1 games you have from PS+ but they have no way to support PS3 games you own from the service.
Unless they give those specific titles free streaming through Gaikai or something but I highly doubt it. Bottom line is that you shouldn't get PS+ now if you are bothered about the fact that the games won't work on PS4.
It isn't exactly about locking you out of stuff. It wouldn't do you much good to have the games on the console if it isn't able to run them.
For example PSP can run the PS1 and PSP games you get for free from PS+. They aren't afraid to give access to different hardwares.