Not sure the market really is moving towards WiFi/BLE - there is a lot of talk about BLE meshing right now, but so far haven't really amounted to much it seems.

The strongest part of 6lowpan meshes right now is that it supports sub-GHz communication, which has much longer range and less interference than 2.4 Ghz.

In the end though it doesn't really matter which radio technology is being used, as long as it gets stable Internet connectivity. Once you're there, the backend is easy to reach.