According to reports from the Wall Street Journal, the Sony Interactive Entertainment Chief, John Kodera, has said that the PS4 is entering the final stage in it’s lifecycle. This means the number of units sold will start to decline, and the lifecycle will end in March 2021.
In a tweet from Tech Reporter Takashi Mochizuki from the WSJ, the following was said by Kodera:
PS chief Kodera: PS4 is entering final phase of its life cycle, which would have negative impact to the unit, but recurring revenue via membership services etc should cushion some of that.
— Takashi Mochizuki (@mochi_wsj) May 22, 2018
This means that the PS5 could be expected in the next few years, and may release in 2021. The PS4 was first released in 2013, and most consoles usually have a 10-year cycle. But Sony would plan to release a new console before the 10-year cycle.