Correction. Move the numbers over one decimal. $1.40 per 10 authentications.
In 2015, 18B authentications per week. 72B Authentications per month. 72Bx12=864B authentications/per year. 864B/10=86.4B
86.4B x $1.40 = $120.96 B X 1% =$1.2B for ACS/SFOR
Or if you go by the $1.40/month per user plan with unlimited authentications and off of the 2015 numbers (350 million Azure AD users), we come up with $490M per month and $5.88B per year. 1% of that gives us $58.8M per year for ACS/SFOR?
And that is just from Microsoft. Again, who says SFOR is not worth $8B?