Comment by keyringlight

Two things that strike me.

One is the "when everyone is special, no one is special" factor, but I think that's tempered a bit by PCs becoming a status item (alongside the rise of streaming that shows the streamer and their environment) so it's important the PC is conspicuous. Also for those that have invested significant time/money it has become a point of pride for them that they want to display, and get into flamewars on the internet to defend their team. The manufacturers probably don't mind that it lets them display their brand in lights too and not be hidden away as a sticker or PCB marking.

Also that there seems to be space in the market for 'PC as a pretty lightbox', RGB systems are sophisticated now alongside LCD systems getting attached to various components. The PC becomes a decoration as opposed to a tool that fades into the background like a lot of other devices which are pure display or have enthusiasts salivating about thinner bezels. The thing I find curious is that the lightbox is constrained in the form of a PC (even if they sometimes try hard to hide the machinery of it such as wires or putting components on PCBs hidden behind panels), there's not a lot of consumer products where you could assemble elaborate colored lighting displays.