People really hate talking about the PS5. They all think it's way too early, and even though it's going to be 5 years old this fall, people want another 7-8 year console life cycle.
The PlayStation on average has been 6 years before the next one but Sony does a great job supporting the old system for at least a couple of years afterwards. That's why 2019 makes sense but the price will be the problem if they want a substantial upgrade.