Again just a wild guess, but in the beginning it would probably have been rather difficult to manufacture a viable nosewheel. I assume most early aircraft were made from wood; the mainwheels would be a frame that was braced, and a simple skid at the back. It would be rather impractical to put something like that at the front.
With the advent of metal airframes, much easier to arrange, but until there's a need, why not stick with what works?