Comment by AlotOfReading

Bright colors fade more noticeably over time, so bright clothing was a good indication of new, regularly replaced clothing. The dyes themselves could also be phenomenally expensive. The scarlet red of Catholic cardinals was historically made from Kermes, an especially lightfast dye. Kermes was in turn a cheaper alternative to the Tyrian Purple worn previously.

Daily clothing would have been more pastel than the saturated colors we associate with "colorful" today.