Is it really possible that an artist (in the broadest sense of a person that performs an art of some sort, rather than necessarily a painter, for example. Perhaps artisan would be more accurate, understood as activity rather than economic activity) can be before their time? If we are all products of our time it is more accurate that they are at the cutting edge of that which drives their epochal shift forward. That is, they are not ‘before their time’ per se, but rather there is a lag wherein the dominant structures of their productive form are yet to be hit and reshaped by the wave that is already being ridden by some. Indeed, that the timetraveller in this problematic is very much a constitutive part of said same wave seems likely.
Of course, only the lens of historical analysis can hope to identify who represents or participates in this progression. There are doubtless many today who could one day be considered to be ahead of their time, but their success or lack thereof will determine what that time is, and where time is going.