Absolutely not. Older DSLR had lower resolution, but level of detail is not all there is to image quality.
Dynamic range, bokeh, control over perspective, the ability to take pictures of moving targets at higher iso without the picture becoming too grainy and the ergonomics are all things that even a 15 years old DSLR can do better than an iPhone 6s.
You just can't get pictures like these out of a smartphone :
These all come from a Nikon D1h, samples from dpreview. The D1h was released in 2001. Nowadays, even the lowest end DSLR will outperform it in almost every single way, apart from build quality. Even so, that old top end camera still outperforms smartphones where it counts from the point of view of art photography. In 2001, I still used film cameras because good DSLR like the D1h were out of my reach, but these days, even a $300 DSLR will just obliterate anything you could do with a smartphone.
And then there's the fact that most casual photography is taking pictures of other humans, and that the wide angle lens of smartphones distort perspective and make people weird up close. The iPhone has a 30mm equivalent which is very unsuited to taking pictures of people.
You can see here how even the 35mm is plainly inadequate compared to the 50mm focal length.
The Nikon D1h, Canon 1D, etc... definitely has better bokeh, dynamic range, perspective control, etc than even the best smartphone camera on the market the today, but consumers just don't care that much about actual photographic quality. They see a DSLR today and think "bulky", "another set of batteries I need to charge", and "how do I share photos to Snapchat with that thing?"
Most smartphone cameras are more than good enough for daylight shots, selfies or Instagram, and if you are not into photography, that's good enough.
I will grant you that I might have trouble getting the shot of the racing car with my current crop of digital cameras. But the other two ... I guess I'm not just seeing the difference.