I am not going to blabber pointlessly about the virtues of a full frame camera vs. a smartphone camera. Instead, I wanted to highlight why the smartphone camera is going to completely replace (if it has not already) the DSLR. Consider the following image I took with my iPhone X in portrait mode - stage lighting mono mode.
The image quality is remarkably good for a quick snapshot. However, blow it up in a 1600 pixel crop and you clearly see the limits in a small sensor camera, one that will not be fixed in the next decade as this is a basic limitation of pixel density vs pixel size, constrained by the physical limitations of a smartphone.
Now consider a similar photo taken with a Canon 5DsR and 135mm F1.8 Sigma lens at F1.8:
And a 1600 pixel crop:
Clearly the much larger sensor in the full frame camera handles noise and resolution much better, even at 4.5 stops higher ISO than the smartphone.
The reason I say this does not matter is because:
In the end, the DSLR will diminish in popularity and become a relic of the past. Even pro photographers find the current quality and efficiency of smartphones to be almost sufficient for a lot of their work.
It is not about which one is better, it is about which one is good enough for the average person. Clearly that is the smartphone.