with all these low sale values should Alamy be added to the "microstock" list ?
It's not the NU use sales that make alamy closer to micro. In fact, and considering the license they are probably closer to nanostock!

What makes alamy closer to micro it's their regular sales. Without entering into specific values I can say that my average sale after the commission, this year and last year, is not that far away from the SS of FL Extended-Licenses values.
And if you consider again, the licenses, they are a huge bargain compared to iStock for example, or any other agency that require several EL's to get the same rights that the alamy license gives as default.