Sure it is. Steam is probably the largest data base for gamers.
Not sure if you noticed what I said earlier about Steam - it's basically missing most of the gaming population from 4 of the fastest growing markets for PC gaming enthusiasts and upgraders (Brazil, Russia, China and India).
Russian - 14.49% of Steam users
Simplified Chinese - 1.63%
Traditional Chinese - 0.5%
Brazilian Portuguese - 0.41%
India?
Steam essentially cannot track the 4 fastest growing markets for PC gaming worldwide because of the Internet infrastructure of those country and prevalence for pirating PC games. Not only that, it doesn't track sales, it only tracks usage of GPUs for people who use Steam. You can use it for yourself but it has no accuracy whatsoever in terms of global sales of GPUs.
Again, as I said when real world data is available for market share, it's pointless to look at Steam not only because it excludes millions of gamers in emerging countries, but also because it tells us nothing about actual sales. You can't infer anything accurate about sales from Steam. Imagine how many NV GPUs are used for Folding @ Home and none of them shows up on Steam. It's simply a snapshot of what GPUs Steam users have, that's it.
For example, the latest Steam hardware survey shows:
ATI Radeon X700 +0.26%
ATI Radeon X800 +0.01%
ATI Mobility Radeon X2300 +0.22%
NVIDIA GeForce 7950 +0.13%
NVIDIA GeForce 7900 +0.25%
There is only 1 problem - you cannot buy those GPUs in retail and haven't been able to for years. If we used Steam #s to infer sales, we would be suggesting those GPUs still sell in retail. This is why Steam hardware numbers are meaningless when it comes to real world sales #s.

The last time i checked AMD announced the 7970GHz end of june 2012. nVidia released the GTX285 end of January 2009 (seven months after the GTX280) and the GTX580 beginning of november 2010 (seven months after the GTX480). Yeah you are right 6 > 7...
You can flash any reference HD7970 with GE BIOS for free if you want. That's not the point though. If someone bought an HD7970 in January 2012 and overclocked it, they
still have the fastest single-GPU (perhaps slower than HD7970 Matrix, but that's still the same GPU family). In other words, unlike GTX280/480, HD7970 still has the bragging rights of being a top dog 10 months after launch. As far as single-GPUs go, you still can't go out and buy anything faster than 7970 OC. Not bad for those who bought it right away in January 2012.
GTX285 and GTX580 superseded NV's previous gen flaships within 10 months of release. Not so for HD7970. NV has no faster card and neither does AMD. For $550, early adopters did pay a premium but in return they got bragging rights of having the fastest single-GPU this entire generation (perhaps early batches of voltage unlocked MSI Lightning 680 were faster with older drivers, but it doesn't matter at the end of the day since constant driver improvements kept HD7970 near the top anyway). HD7970 lost less than half of what GTX280 lost in value during the same period of time. HD7970 also lost less than 480 did during its cycle. I remember when GTX570/580 launched, GTX480s were readily available for $299 on Newegg. In North America, HD7970 users even had the option of bitcoin mining on the side, which means by now the card has been fully paid off.
With
latest drivers, HD7970 owners are looking at a card at least as fast as a GTX680 and they paid just $50 extra 2.5 months before GTX680 even launched. That's not really a rip-off for early adopter enthusiasts who know that by buying the latest and greatest, they are paying a certain premium for the bragging rights. GTX280 & 480 owners paid the premium and that turned out FAR worse than it did for HD7970 early adopters.
BTW: My GTX480 run at 840MHz, which was 20% faster than stock...
It wasn't faster than GTX580 OCed though. What card can an HD7970 owner get now that's faster than his GPU overclocked? Maybe Asus HD7970 Matrix. But some people who bought HD7970 Lightning hit 1250-1300mhz overclocks earlier in the year. For them there is still nothing faster from either NV or AMD. HD7970 continues to be a premium GPU offering 10 months later, having lost less in resale value than did either the 280 or the 480. Was it too expensive at launch? Ya, but early adopters know they are paying a premium.
Your logic works both ways. HD7970 was too expensive to start, but GTX680 has been overpriced based on its performance for at least 5 months now since June 2012. If you say that HD7970 was overpriced, well now you can get HD7970 1Ghz with 3 free games for $380. Using the exact same reasoning you used to say that HD7970 was overpriced, that means GTX680 was also a rip-off since you can now get similar performance for $120 less. What's your point exactly, that GPUs get faster and/or cheaper with time as that's how the technology cycles work in GPUs? I don't remember NV users saying how much of a rip-off GTX280/480 were though in terms of depreciation or early adopter premium for 280.
The best part about HD7970 is people who took 10 min to set up bitcoin mining, got their cards for free. GTX280/480/580/680 cannot claim anything of this nature. That made HD7970 for $550 a good deal actually for some buyers.
