Airvana’s strengths are in the CDMA market, where they are having good success - for example with KDDI and Sprint.  If they have chosen to focus on CDMA (and LTE) at the expense of UMTS then that would not be a huge surprise, but I doubt it's a consequence of an imminent threat from the Taiwanese ODMs.

Although the low-cost manufacturers working on a reference design using a 'chip and stack' approach have been attracted to the much larger UMTS market, the idea that they will find success easily and quickly is wide of the mark.  To deploy femtocells successfully in a real-world UMTS network takes a lot of experience, and also significant investment.  Demonstrating features in a lab is one thing – being able to mange widespread real world deployments is completely different.

In truth four manufacturers can currently achieve that in the UMTS world – ip.access, Ubiquisys, Alcatel-Lucent and Huawei – and that makes for a healthy and competitive market.