Re: So, it's a PC, right ?
Doubtful they learnt the lesson well with the original Xbox, used to run xbox linux on one of mine (had 3, one for gaming/going to block buster and hiring 5 games for a £5 for the weekend and ripping to the upgraded HDD, one as a media center xbmp => xbmc aka kodi these days, and one as a simple web and mail server).
Instead i predict inside you will find a single big PCBpossibly a wifi daughter board as its cheaper to just plonk a standard laptop wifi board in, a bunch of heatpipes and hopefully and inch or 2 void at the bottom for a dust catcher and means to not choke the thing if put vertically on carpet, as the fan would be sucking bottom to top. And yet another huge PSU brick as that makes manufacture easier, you only have to design the psu for each major markets power network/standards
Will be interesting if MS also do a PS5 and have an SSD cartridge, as i reckon that digital only will be a non starter for anyone on a sub 30Mb connection 80+GB downloads for games and 40GB day one patches, would not be at all surprised to find self serve vending machines in super markets and games shops to copy to the SSD