Boy, it would be sweet if ARM or someone would sponsor some kind of common system architecture. Sure, lots of vendors would keep making their own boards like Pi, beagleboard, ODROID, etc. But having an extensible architecture like UEFI or similar to facilitate bootstrapping while still being open would be awesome.
They already have done all that:
hardware: https://www.96boards.org/
boot: https://github.com/ARM-software/arm-trusted-firmware
toolchain: http://releases.linaro.org/14.11/components/toolchain/binaries/