Yeah but there are several standards for each component. Like for bikes (which I understand more) there are the 622mm wheels (700c - 28" but also 29" which is confusingly the same rim diameter but wider rim), 635mm wheels, and then 26", 27.5", 24", 20" and some smaller ones. Not sure what size wheels are used on fat bikes... And then you have QR axles and thru-axles in 100mm, 130mm, 135mm, 142mm and 148mm sizes and some other and usually 15mm or 12mm diameters (except the QRs that are 5 or 9mm). Equipped with either rim or disc brakes, for each brake type the rear (and sometimes front too) axle size will probably be different. Then the rear wheel has a freewheel on which the cassette is fastened unless you use a internal gear hub (like Rohloff).. so the freewheel is one of I think 2-3 different Sram types, 2-3 Shimano ones, 1-2 Campagnolo and maybe some other. And so on. So there are certainly standards. Lots of them.