Recent efforts like phoneblocs have caught everyone's fancy (more than 1 million have signed up for them, including me). As the smartphones continue to improve at a breakneck pace, the marketing done by all phone companies(like the new feature their latest phone has is the greatest invention since sliced bread) leads to consumers buying phone (and tablet) devices even when there is not really a need to purchase them.
Such purchase and throwing off phones every year by enthusiasts is increasing the generated e-waste. It only benefits the mobile vendors, who can proudly proclaim their sales figures.
While phones can be broken and be easily re-assembled according to user needs, as explained in the phoneblocs video, there is another need to free the phone boot-loader/bios away from evil grips of software. Currently iOS or Android is created which only runs on a particular system on chip(SOC), or hardware. Projects like idroidproject exist, but are lacking driver support and community.
Hopefully with the advent of web based mobile os like mozilla, the dream of dual and multiboot mobile os can be made a reality - which could be a lifesaver for old phones with limited hardware constraints, but can support new UI altogether.
Ubuntu touch has demonstrated their OS on many android devices and is moving into the right direction while building a community. I am hopeful that other providers like google and microsoft take note and provide this interchangeability, which in turn will allow phoneblocs to be truly vendor neutral.