Whats the real reason people prioritize the rear derailleur when building a bike from scratch - is it truly about performance and shifting quality, or is it more about perceived importance and the fear of not having the latest and greatest technology, because it seems like a well-functioning front derailleur can often be neglected in favor of a high-end rear derailleur, and yet both are critical components of a smooth-shifting drivetrain, so why the emphasis on one over the other, and do manufacturers play a role in perpetuating this bias, or is it driven by consumer preferences and perceptions of what makes a good bike.