[Derpy McBlueEyes]

I don't make art, so I can't offer advice or anything from that point of view, but from the perspective of someone who has bought art back in the day (granted, 99.9% of the time, it's been online currency only, not rl cash), I feel like it's kind of a given that artist's skills and styles will evolve and improve over time, so it's never bothered me to pay for art and later see an artist having higher quality art.
Not sure if that helps or not though.