I’m also “old” (44) and feel that rainbow LEDs are gaudy.

Seems these days that they’re not optional for most things remotely gaming related (e.g. motherboards, graphics cards) , but fortunately can generally be disabled or if illumination is useful (e.g for a keyboard), they can be configured to be white only, which was useful for the Steel Series keyboard I purchased. (I wouldn’t recommend Steel Series keyboards though, has stupid design choices and reliability issues.)

Also did LAN gaming back in the day. Computers were so much more work to lug around when you had a CRT and HDDs. These days desktop computers are far easier to transport.