Ehh, I haven't crunched the numbers, but that's not necessarily true. Instead of taking a still picture, use video to take a few images and generate a rough 3d image. While I don't think the initial face recognition on Android had it, I believe they (or someone else) did later.

I have no idea how finger print vs facial recognition compare in accuracy, but a decently implemented facial recognition system shouldn't be compromised by a still image.