Pro Photo is good foresight as when it was conceived the computational horsepower was not at all there but the colour scientists saw it as a spring board covering many years if not decades of photography in a digital format for every use of archiving and transmission for multi purposing of the images captured, recorded, created, etc.
Capture has been and is using a large part of the colour space, some new monitors are able to surpass the monitor derived Adobe RGB, and many printers are reaching out farther and farther into the Pro Photo space. In the next ten years the devices will surely go farther into the images potential if recorded or passed through this space.
If anything it is the ICC who should be quicker to adopt some of the propositions that would better exploit the use of the maximum potential of capture and or images sing large parts of Pro Photo.
Like in the film days, Pro Photo is the largest tool , the most colourful view out of the lot which will be the king for a long time to come as if it were Kodachrome compared to Ektachrome or Velvia compared to Astia. Even if you use it for imagery that don't go beyond the limits of lesser spaces, it costs no more to preserve the potential in every image.
Already with some users moving up to any of the new printers like the Epson x900, Canon iPGraf, or HP Z3200 if when reprinting the image previously printed on lesser gamut printers, from ProPhoto and or traversing through fetch a remarkable difference and gain by pushing the boundaries.
Why would you want to do without?