Sony will be at Gamescom, as they go to a ton of events. But to make business behind the doors, without having a booth to showcase games to the public.
A few weeks ago Yoshida came to Spain to scout indies in a small indie games event. So obviously they'll be at Gamescom too.
They are obviously working on things but not ready to disclose. That would be fine except there should be a consistent pipeline where things are in a show ready state while the next batch is in progress and so on. Again, this is Xbox like behaviour - the inexplicable drought.
Pretty sure their GaaS aspirations derailed the tried and true path.
For these year TLOU2R, Helldivers 2, MLB, Stellar Blade, Ronin, The Final Shape, Astro, Concord, Until Dawn, the PC ports, also Convallaria and Lost Soul Aside... sure, super drought. Like a desert. xD
Now seriously: Druckmann explained in the Grounded 2 documentary that to make these gameplay demos for marketing (even just for a trailer) take them a lot of time and resources. They prefer to make less and closer to release to optimize their resources and put less pressure on the devs (also helps to get less complains about changes or "downgrades").
If they don't go there, in the same way they also stopped going to E3 is because they think isn't worth it. It's a huge investment and they may have considered that is more profitable and effective to spend that marketing money instead in online marketing, and when makes sense putting a demo in the store.
Biggest gaming event in Europe and they don't go... Right.
I assume that if they have some trailer to share and don't have a State of Play around these days they'll give it to the Gamescom Doritos Night Live.
It will be seen online by more people than if they put it in a Gamescom both.
Worst of both worlds.
