I recon less than 5% of people make money selling Blitz3D games.
I reckon less than 1%. But I'm probably basing it on a larger userbase than you are. There was a poll once about how many projects people had completed in Blitz. If memory served roughly 1/3 of those who took the polll answered '0'. Now I know the poll isn't representative, and thus not statistically sound, but it's an interesting (if slighly disturbing) thought none the less. And then when directx 9 came out they screamed, WE NEED DIRECTX 9!... WE NEED DIRECTX 9!.
You'll notice that the same people who are now "screaming for DX7" as you so elegantly put it, where roughly the same people who said "Why would you want (much less need) DX9 when DX7 hasn't even been pushed to the limit yet" whenever someone came by "shouting for DX9".