The possibility is already there, the question is when do you jump into it. Similar to PCs in the early 90s, some did jump into (GNU/)Linux already in ca. 1993, while I did only in 1997, and most people only after Ubuntu shipped et cetera. Now I jumped into free software on mobile phones in 2008, and I'm quite happy to stay there even if it will be until eg. 2018 when there's a "Ubuntu of mobile phones" there (and yes, even Ubuntu hasn't got a big market share at least yet, even the installations are in tens of millions). MeeGo seems to be a possibility of that date being earlier, and actually in better pre-installed amounts than Ubuntu. But the whole free software ecosystem is also so much more mature nowadays that the date can be quite soon if UI work and modem drivers are done. The needed middleware is there already, FSO (or oFono) + Qt/E17(/GTK-Clutter), even though FSO and oFono would both enjoy more contributors.
The mobile phone market really starts to be on the edge of commodity market, with Openmoko phones and reverse-engineered selected (older) Android-shipping hardware and Nokia N900 out there, plus the promised probably quite nice MeeGoish device from Nokia. One needs to spend time with any of those to use free distribution on the phone having the phone as the one to rely on, but for me desktop Linux is already so ready that I'm happy to have this mobile challenge and possibility to contribute in a meaningful way.