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:

1. Most people only want to share their photos online, and consume them online. Online, on a device such as a web site or smartphone screen, the iPhone image looks stunning. The noise and processing artifacts is near impossible to see at reduced enlargements. Only when you blow it up on a large monitor, or when printed, will you see these limitations.
2. The iPhone with its modern portrait mode and other auto processing functions, especially instant sharing, takes the convenience factor to a next level - one that the full frame DSLR simply cannot match. This convenience will win out 99% of the time for most consumers.

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.