Nope, not bec of cost. Both the AC Ryan and the Aztech can be bgt for less than $200 which is not much more than a good MIC android box.
For me, the MIC brands are more advanced than the brands u mentioned in terms of both hardware and software and the pace of development is much faster. From the Rikomagic MK802 to the MK II and then the MK III versions; then to the UG802, MK808, Minix Neo G4, X5 etc - the improvements keep on coming.
In contrast, while AC Ryan makes decent media players, their Android attempt (i.e. Veolo) has been mediocre. Can u believe that it is still running Gingerbread!! And there will prob never be an update to ICS because of AC Ryan Europe's problems.
As for Aztech, I have always been disappointed in their products in the past - from routers to wifi plug-ins to phones.
Unlike tablets, there are relatively few big branded names doing android boxes only niche companies like AC Ryan, Astone, Aztech etc.
Companies like Sony, Samsung, Toshiba, Asus, Acer are all active in tablets but don't seem to be interested in android boxes so the Chinese companies have sensed the demand and grabbed the lead - at least for now