It's all relative.
I saw this article in the Times today and was immediately struck with this quote:
Mr. Thompson, who has been struggling to succeed for more than a decade (he turns 35 on Feb. 19), has enjoyed only marginal success in the United States — his average record sales are 21,000 — and is acutely aware of his dwindling shelf life in a business with a rapid turnover of talent.
So 21,000 albums? That’s quiet a bit if you consider that many independent artists would kill to have that many of their albums sold per release. It’s not anywhere near the historical numbers many of the greats hit, but it’s respectable nonetheless, and I think underscores the way that people still look at the music industry through the lens of the old system.
I understand also, that to sell that many albums puts you into a category of musician which is closer to “cult” or “niche” rather than in the orbit of “mainstream”, but that doesn’t rule out respectability or influence.
So, take a look here to see for instance, how the top Pitchfork 50 for 2010 sold. The top is Kanye West with 915,391, but some of these bands were hovering around the 20k mark as well, and a few were even below 10k.
But I also know that 21k is not 915,391 either!