Displays are already moving towards wider gamuts. I believe that newer iPhones, for example, are all P3 displays. So there is no doubt that sRGB usage will be replaced by wider gamuts in the future.
There are really 2 important questions here:
- Which gamuts will people end up using?
- When can/should we move our apps to using wider gamuts?
The answer to the first question will depend on the market. People have been pretty happy with sRGB for a few decades. P3 is better, but most consumers probably can't tell the difference. There are much wider gamuts like ACEScg, Rec. 2020, etc. Will it be affordable to move to those? If it is, will consumers care?
The answer to the second question depends entirely on what your target audience is using. If you can guarantee they're using devices with P3 displays (say, if you require the iPhone X's IR sensor), then you should move to P3. If your users are high-end users creating output for professional use, it's probably wise to move to P3. If your users need to create content that looks reasonably good on end-user devices like web pages rendered on aging machines, then it is probably a waste of effort to move away from sRGB.
Note that there is a cost to moving to a wider gamut. You will need to do significantly more work to ensure that all of your processing is done in the right color space because input images to your app will likely come in a variety of gamuts and you now have to convert them all to your working space, process them, and then convert to the output space. That's not cheap to do and not easy to get right.