Our family uses three Macs.
The Boot Camp workaround is not appealing. We use our computers for work and Brill Kids will be the first software that we would have to consider using Windows/BootCamp to run. We have no interest in shelling out the cash for Windows to merely run Little Reader.
As I'm sure you are aware, this headcount forum is unlikely to reflect the number of potential Brill Kids customers who use Macs. I suggest that you use hits to the No Mac OS page as an indicator of market loss.
http://support.brillkids.com/index.php/article/will-brillkids-software-work-for-mac-os-users
Even then, hits to this page only reflect potential buyers who are willing to inquire further after reading, "COMPATIBLE WITH WINDOWS ONLY.", on the product feature page.