Earlier quoted context omitted.
If you are so convinced then why don't you correct the wikipedia article? Perhaps also call up LSI and Adaptec, who use the same formula in their documentation. http://storageadvisors.adaptec.com/2005/11/01/raid-reliabili... But what do they know, they only build raid controllers...
You're right, there's no reason to try to correct the 20% of the population that believes the Sun revolves around the Earth. It's a lost cause; you win.
Erm wait, didn't I just suggest the exact opposite?
If you really think everyone has been wrong about this all the time then please, by all means, correct wikipedia or write a blog post about the matter.
This "false" formula has been out there for quite some time and you find it in pretty much every write-up on the topic, including those from RAID-vendors who (I'd hope) have spent some thought on these things.
On the flip-side I haven't found a single source to support your thesis. Thus I'd say the burden of proof is on you.