EOSM is late to the market, which means that to make any headway it needs to be a very compelling offering in order to get traction. Given Canon's current weakness in sensors and its decision to put a so-so AF system in the EOSM, I for one am not to excited to 'lock' myself into a system with just a few lenses. There is just no sense in doing that.
Despite having all Canon cameras, I ended up replacing my S90 by a Sony RX100. That camera is so good (size, lens, sensor, AF), that I'm now doubting whether the premise underlying the EOSM is viable at all. Rather than carrying interchangeable lenses, I could see myself carrying two RX100-type cameras with different lenses.