Can one large size favicon serve all devices and browsers?

Question

All discussion about favicons recommend creating favicons of different sizes to target different clients. See this answer for example: Does a favicon have to be 32x32 or 16x

Answer 1

Some browsers could scale it down; however, IOS currently doesn't support favicons, so it would be completely useless to make one for it. Unless you want to add it into your text file whenever Apple does build the support for it.

I would recommend going with a 16x16px size, since it has less memory attached to it.