No, the stance is the same. It's up to the developers whether or not to make use of PS Plus. If they want to remain outside that ecosystem, they have to agree that with Sony, and provide their own online service components. There is still some integration with PSN, but PS Plus is not needed. People seem to have some kind of compulsive need to imagine otherwise, but it's not the case. Now, considering that providing your own infrastructure isn't cheap, I can see why many devs choose not to do that. Also, additional features available specifically through PS Plus may be part of what they want to offer their gamers.
But, at the end of the day, the simple truth is that technologically speaking, all that is needed to play online with PS4 is PSN for authentication and license checking - so long as the game supports this. PS Plus isn't needed, and no amount of mental gymnastics will make it otherwise. Also, this has nothing to do with PS3, it's Sony policy.
Oh, and BTW the uptake rate for Gold membership with Xbox 360 was no where near 100%, it was closer to 60% and I've seen nothing to suggest that it's any different now. It's most certainly not 99% of Xbox gamers.