Low-tech Magazine was born in 2007 and has seen minimal changes ever since. Because a website redesign was long overdue — and because we try to practice what we preach — we decided to build a low-tech, self-hosted, and solar-powered version of Low-tech Magazine. The new blog is designed to radically reduce the energy use associated with accessing our content.
Sure, but one difference is that new data-centers get build all the time because of high demand. If some of that is substituted by hosting on a SBC from home, then that is probably a net positive for the environment.
So your bus metaphor is only half applicable, and the choice would be rather between upgrading an existing bicycle with an electric motor Vs. building and running a new diesel bus.