He is an ICON of RockNRoll. His look, his style, vocals, and his theatrics helped create the mythology of Led Zeppelin and created what a Front Man should look like which was formulated in almost every RNRoll band from then on. He took Daltry's look and style and amplified it. Zep, then considered the "progenitors of Heavy Metal."
Sure you could put someone in his place but then the combination wouldn't have created this, one of the great RNRoll bands ever.