I think the Matchroom events will mostly continue to use 4" pockets, but other tournaments/money matches/pool halls will not adopt them to the point that they are considered standard in the near future.
4" pockets have advantages and disadvantages. It's entertaining to watch pros struggle and know that they could miss at any moment. It makes the skill standard of the game seem higher. But it also kills other sources of entertainment by necessitating greater focus and preparation on the part of players at the expense of their rhythm, confidence and creativity. Sometimes, it's entertaining to watch someone fly around the table stringing racks and putting a big stroke on the ball when they feel like it, and shrinking the pockets discourages that.
But here's the main problem. Tighter pockets breed more deliberate players, more misses and more safety play, all of which slow down the overall progression of a match. Therefore, televised events will need to include shorter races to compensate for that time. Shorter races are more subject to "inequitable" outcomes--just look at Lo Ho Sum's notoriously choppy run to a 2nd-place finish at this past weekend's Masters.
My opinion is that there should be one or two major tournaments per year played on 5" pockets with a winner-breaks format and significantly longer races. I think the standard of entertainment in those matches would be very high and I think there would be fewer silly upsets.
