Not only that, but something I didn't realize until I went to the Playstation subreddit. 2020 is the 25th anniversary of the Playstation brand. Sony will want to make 2020 the year of the PS5.
I also think they took a lesson from the Switch and are going to hold over Death's Stranding, TLOUp2, and Ghost of Tsushima until 2020 and make them cross-gen titles to help boosts PS5's launch year sales.
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Actually, next year is the 25 anniversary since the PS1 launched in Japan in December '94.