If you don't see how its better then jesus christ, i don't think anyone could explain it to you. For a start, the CPU difference is vast. A Zen2 processor in the S vs the Jaguar in the One X or PS4 Pro isn't even a competition, the Series S will benefit from far more reliable and higher framerates in general as well as keeping the console itself fast and snappy all round. Old 7200rpm HDD vs NVME SSD? again, no competition, the S will demolish load times like the X by half or more. Xbox One X uses 12gb of GDDR5 RAM, the S uses 10GB GDDR6, and although a smaller amount, the GDDR6 is newer and faster. They'll only have 8gb to use after OS usage but it was designed that way on purpose for 1080/1440p instead of 4K.
Everything about it on a technical level is better. It's newer, has newer chips and design. It's just better. The One X will do 4K yes, but at a max of 30 at best and that's before analysis is done to show frame drops and resolution scaling down.
People are focusing too much on resolution while having little to no knoweledge in anything technical. Just because one can output at a higher res doesn't mean it's better, that's only one slice of the pie and not the main focus of a game dev. If you value gloating about resolution numbers then you will never be convinced, but anyone with a brain can tell you its hands down better, just scaled down in it's own playing field.
The problem is shitty developers who don't knuckle down on optimisation, it's as simple as that. 900p in Yakuza is down to the developers choices to focus on other parts of the game while neglecting to setting and hitting a target resolution of 1080p+. They could've, but chose not to, thats on them. Same goes with PUBG, from the very start it has been one of the most poorly optimised titles on the gaming market. It has N64 level textures for christ sake. Anyone using that as an example of poor performance on the S should be called out and laughed out of this forum for their stupidity or ingnorance. It's funny that people focus on the bad but then ignore games like Dirt 5 who are great at omptimising their game on the S. Many other devs have said good things about it, but that's ignored in favour of concern trolling.