I'll focus (pun intended, of course) on the title:
Should near future smartphones replace professional cameras?
No. The reason is that a digital camera really has three components:
The sensors of the best professional cameras will likely always be a few steps beyond the best smartphones. That is because smartphones (and any multifunction device in general) are a compromise based on cost, weight, size and other factors. The camera function of a smartphone is only one of many things it is expected to do, along with email, web browsing, maps, texting and even (really!) voice calls. If everything were at the highest level, the cost would be prohibitive and/or the device would be huge. So the sensor in a smartphone will typically be a generation behind the best sensors available (to save money). That being said, the sensor in a current model smartphone is likely better (at least in raw number of pixels) than the sensor in a professional camera from just a few years ago.
Processing is not fundamentally different between a smartphone and a professional camera. However, the typical smartphone will, by default, produce a JPG image of relatively moderate resolution & quality. That limits some of the possible image manipulations that can be done on a computer if you are able to start with RAW data. It may be possible (likely is, I haven't tried) to get RAW images from a smartphone, but that is a standard function of a professional camera.
This is by far the biggest difference. A typical smartphone has one tiny lens. A typical professional camera (digital or film) can accept a variety of lenses of different sizes optimized for different uses and can be adjusted as needed to get just the right shot. A smartphone typically has a "digital zoom" capability, but that is (mostly) image manipulation and not an actual lens adjustment. High-quality lenses make a huge difference in image quality, especially when going beyond simple portraits or other nearby objects.
The end result is that for the foreseeable future there will be a market for professional cameras for professionals and serious amateurs. At the same time, as smartphones continue to improve, they are able to capture more and more images at higher and higher quality and, particularly due to convenience (always available) and effectively unlimited memory (able to take multiple pictures where in the past you would try to get just one and hope for the best), allow ordinary people to take some pretty amazing pictures.