I've been a 2019 believer since.. whenever I decided to put a flag in predicting it - for the reasons below:
1. The 'length' of the generation. Anecdotally speaking - on the first-party side it was definitely seen that the previous gen was too long. It was 7 years for the PS3->PS4. A PS4->PS5 in 2019 would be 6 years.
2. Symmetry. With PS4 in 2013, PS4 Pro in 2016, and PS5 in 2019, it pegs the 'mid-gen' squarely in the exact middle of the base model and next-gen model, and that sets a good timing precedent for future audiences.
3. The 'cross-gen' reality. Early PS4/XB1 was wrought with many, many games that were available for both generation of consoles, since AAA games are expensive and most 3rd-party publishers will not risk releasing a game strictly for the highest spec consoles. That means even if PS5 and XB2 are released in 2019, there'll be approximately a 2-year maturation period as games transition from cross-gen to next-gen. IMO, cross-gen actually incentives that next-gen consoles are released sooner than later - since it means that the current-gen console base would still be relatively healthy while next-gen transition are going on.
4. Sony's lack of announcements this E3. Say what you want about Sony - they've never been gun-shy at revealing games early. While it's true that TLOU2, GOT and DS could very well be 2020 games, there's actually enough empty space in the 2019-2020 space of games that they could afford one or two announcements but there was none of it even at their biggest stage of the year. IMO, that means that they were not able to - since any game that isn't announced at this point ( AAA-level ) are PS5 only games.
5. The 'success' of the PS4. Unlike some of you, I believe that the success of the PS4 is all the more reason to accelerate the release of the PS5. I believe that the most rational and ideal business execution of the PS5 is not to wait until PS4 is sunsetting in it final year, but to release in the first year of its final 3-years. That way, PS5 will benefit from a relatively mature 2-year cross-gen period where PS4 is still a healthy console rather than one-year good and one-year sluggish. And I definitely think that 2019 will be "Year One" of PS4's final 3 years of significant software support.
6. I don't believe that next-gen console are defined by leaps in hardware technology - but in the best business timing that matches with a significant enough improvement to be able to sell the next flagship box. You need both - and while 2019 might not necessarily be the best timing from a pure technology standpoint, it'll be enough imo - for something that is 8-10x more powerful than base PS4. Enough to sell a generational leap.
7. MID-GEN. DOES. NOT. EXTEND. THE. LENGTH. OF. A. CONSOLE. GENERATION.
