You assert that "if every phone has a different screen size and processor speed then applications will still have to be ported between them" but that is definitely not always the case. A good OS and GUI manager should be able to manage screen size and processor speed dependency and provide applications with knowledge of available resources. This works quite well for Symbian + Series 60. I think the real problems come with version changes, ie. moving to Symbian 9.1 - much better access to the hardware but breaking backward compatability and, of course, developing for Series 60 is not the same as doing UIQ.
As for LIPS - it's unclear from your article whether the spec is high-level - how applications should work with each other - or low-level - you can use these libraries, like this. Will LIPS work across the various competing GUIs (QTopia, et al.)? In any case how big is the market for apps for phones?
My understanding is that Linux is only getting support from manufacturers because Symbian is too slow and too bad at supporting the new hardware and no manufacturer really wants to be dependent upon Microsoft. But all they really want is the kernel and drivers.