> On consumer devices, picking through file hierarchies is a lot more painful due to input method limitations.
This is a bad interface limitation. Just consider an interface that presents 10 000 files as a 4 level hierarchy with average 10 items per level based on whatever heuristics/preexisting folder structure grouping. Then each file is reachable within 4 clicks or touches even on a small display. This is way faster then a keyboard search on a touchscreen. Plus such search does not work well if one is unsure about the name while grouping allows quickly see neighboring groups/folders providing valuable clues.