Sony finally offered up a detailed public explanation on what's going on with the free but absent PlayStation+ version of DriveClub. It's not good news.
Message from Shuhei Yoshida - President of World Wide Studios

Hi everyone,

I wanted to provide you with the latest update on DRIVECLUB. Unfortunately, the road to launch has been a little rocky, and we are truly sorry that so many of you have not been able to enjoy everything that we had hoped DRIVECLUB would deliver.

We have been listening to your feedback and realize that patience understandably is running out. Evo is working around the clock to close the gap, and we have deployed additional engineering resources to help resolve the remaining issues as soon as possible. Unfortunately, the time frames required to roll out the fully connected experience will be longer than anticipated and we do not have an exact time frame for when they will be resolved. We will continue to update you on progress and you can find the latest info on the DRIVECLUB Facebook page.

We are also very conscious that we have disappointed so many of you who were looking forward to playing the promised PS Plus Edition. Our first priority is to provide you with the best possible experience while playing DRIVECLUB. With the high volume of new players and additional server load the PS Plus Edition is anticipated to bring, we are currently not confident that we can guarantee the best online experience. Until we can ensure that everyone can enjoy the full social connected online experience, we will be postponing the release of the PS Plus Edition until further notice.

On behalf of WWS we are enormously grateful for your patience and we thank you for the continued support and encouragement. Again, we sincerely apologize for the delay. We are committed to giving you the best racing experience on PS4 – it’s taking a little longer than we hoped.

Thanks,
Shu

Bummer