The paradigm of paying to maintain and update the browser is and has been an integral part of MS' marketing in the past, especially in regard to the retail/personal home user. I do not feel that they can compete in that venue anymore as in many ways the open-source community has shown that structure to no longer be competitive. Just my opinion, but the IT area is no longer whether open-source will shift the paradigm, but how does a company compete with user groups that realise/have access to equally stable and efficient code with which capital is no longer attached to a 'product' per se.