That is an EXTREME case. May I ask how many of you have put the EOS-M with 22mm lens in your own pocket or your wife's purse? That is what the EOS-M is for. If it is done right, we can still put a FF mirrorless with a 35mm lens in the wind breaker jacket easily.
My point being that there is a place for both large and small cameras. At some point, somewhere down the road I think it's likely that all cameras will be mirror-less, but just because you can make them smaller, doesn't mean there won't be a market for larger cameras as well.