So Xbox Series X has been announce and it has 12 teraflop RDNA performance that's equal to RTX 2080 Super more or less, plus Ryzen 3000 8 core 16 thread and SSD Nvme as standard. I bet what we see is the new bare minimum for multiplatform games that will be coming to, Windows Store, Steam , Epic Store , GOG , etc etc.
But to mitigate some bad port games, usually it's saver to upgrade to a slightly better hardware then the consoles spec, of course as PC gamer if you want playing on PC is better buying more expensives part then the consoles, because you buy PC to have more than just games that look the same, but want to have better performance than the consoles.
So minimum requirement are:
GPU Nvidia 2080 super is bare minimum but if you want more premium it's probably buy 2080 Ti or wait for AMD RX 5800 or RX 5900 or perhaps wait for Ampere with 3080 or 3080 Ti.
CPU probably going to be big, 8 core , 16 thread will be standard and minimum requirement
SSD perhaps a little bit leeway , but Nvme should be the most obvious although SATA 3 is still playable but SSD is must for next gen,
For RAM , i think 16 to 32GB of DDR4 RAM is suffice for now.
Of course that if you are looking for 4K gaming, there is still be some people who play on 1440p or even 1080p. But Next year Nvidia will release new GPU based on 7nm+ , we will see new standard even on PC gaming. 4k will be standard
So prepare your money