Considering it's what goes under layers of components into a chassis and is a bother to take out if the board is the one that's died due to a mishap, it's often looked as something you buy once and then forget about. It's also why most of us try and look for as much features packed into a board or boards that tick all the right boxes for a build, whether it's good audio, aesthetics, wireless connectivity and overall it's pricing.
Personally, I don't know of any platform akin to PCPartPicker but that's only when trying to pass on a build proposal and even for ease of use on the forums. I tend to nitpick each part/component for a build if I'm going to build a system. Forums(not just this site) help in clarifying whether what PCPartPicker is saying is right or wrong, as PCPartPicker have been wrong on many occasions.