Points to consider
* It may be possible to achieve 20,30 or 40Mb/s over 5G. But it that for all users covered by that cell at once, or just one lucky punter?
* "The average consumer uses 8GB a month". That may be the case on 4G data, but on home broadband (which they're saying 5G can replace) my kids are currently eating 200GB a month on Netflix, Youtube, Snapchat, Facebook, et al. That doesn't include my or my partner's use for work.
* Indoor coverage is getting more important. The problem is that the carriers don't see that as their problem and expect you to pay for your own indoor solution. For an average building, we're seeing quotes of £250k for setup fees. (This is a proper in build solution, not the mickey mouse femto boxes the carriers fob their consumers off with which barely work in corporate environments).
In the past, WiFi was used as a fill-in for 3G. I think that's going to flip now: 4G (&5G) will be the fill in for WiFi.