Why are cycle components so heavily branded?
Up until the mid-to-late-eighties bicycles were not heavily branded. Frames bore the manufacturer's badge on the front, had the manufacturer's name on the frame and had the model name on the frame. Components did bear their manufacturer's respective names, however, these were just stamped on. You could read them if you wanted to. In rare exceptions these secondary brandings were anodized on.

Then a company called Shimano came along with the innovations that were to define the mountain bike in a groupset - indexed gears, cantilever brakes and so on. None of these parts were branded as before, with a simple stamp into the alloy/steel. Alloy parts had big anodized logos, plastic covered gear levers had stickers on them carrying the Shimano name.

The success of the 'Deore XT' groupset led to the introduction lower down in the market of Shimano's 'Exage' groupset. This had even more plastic parts and lots of 'Shimano Exage' branding.

Shimano brought in practices that today are deemed to be 'anti-competetive'. They made bike manufacturers wanting to use their superior indexed gears also use whole Shimano groupsets. They were not able to mix and match components until SRAM came along with their 'GripShift' rival to index gears. SRAM took Shimano to court and thereafter got a foot hold in the market.

Until the SRAM challenge, almost every bike at a given price point had identical components from Shimano. High end bikes had 'Deore XT', lesser models had various 'Exage' parts. Due to how good indexed gears were from Shimano the competition practically did not exist. The Yen was low at the time and European brands could not compete on price, even if they could make a half-decent set of indexed gears.

With every bike being practically identical mechanically, how was a bike manufacturer to command a premium for their products? One way was to go for a better finishing kit (seat, handlebars, grips etc.) Brands such as 'Syncros' came along to offer better handlebars and they adopted the big sticker branding pioneered by Shimano rather than go for the subtle stamp of yesteryear.

Thereafter the die was cast. Even though today bikes don't have to be identikit Shimano, they have the rash of stickers pioneered way back in the days of the mountain bike boom years.