A cpu is basically an internal part. Under what circumstance would you 'see it'? Aside from placing it into the socket and once that 5min is over that's it. A cpu is going to have a cooler of some sort attached whether passive, ln2, air, aio, custom cooling loop. They all involve a water block or heatsink of some form that directly covers it.
Yes, some parts of a car's engine can be chromed but the internals? They don't make valves and pistons with the mudflap girl on them because they're literally an internal part and any aesthetic design would interfere with performance which is the whole reason they exist. Cpu's are flat for best connectivity contact and heat dissipation. You can get an led cooling fan, an led waterblock etc. There's a reason the inside of a car's wheel doesn't have led lights behind the bead, it's going to get covered by the tire and would be 0% visible.
It's not to make fun of your question but it's a matter of visibility. Anything with aesthetic design should be visible or it makes no sense. Ram has led lighting because in some builds, with a windowed case, unobstructive aio/water cooling cpu block, the ram is actually visible. The visible part of the cpu is what's on top and that's the cooler. Leds and inscribed or laser etched images do appear on coolers, their fans and heatsinks. By the same token it wouldn't make much sense to spring for color coordinated sleeved cables and led fans (internally), led ram and such for a pc case that has no window. That's like decorating the crawl space under your house with christmas lights, people generally stick to the tree, windows and outer trim of the house. Things where it can be appreciated.