Softbank was startled by large signups for fixed wireless in Tokyo, a city with almost 100% coverage of fiber home. T-Mobile in Austria has also seen a trend.
The new customers were primarily young. They wanted a service they could take with them if they changed apartments. The fiber connects and reconnects are a headache.
Softbank has nominal speeds of hundreds of megabits and practical speeds of at least a couple of dozen megabits in most of Tokyo. That is enough for most people, most of the time.
Unless they download heavily, most people don't often need speeds of hundreds of megabits. Two HD TV stream and plenty of surfing fit easily into 12 megabits.
Softbank is a world leader in Massive MIMO, putting 64 antennas on cell towers to increase capacity. That typically increases throughput 3X or more. Often, the improvement is 10X.
Softbank has tuned their massive MIMO to give better performance at the edge of the cell site. With that many antennas, you can direct the beam to the area most needing coverage. While the headline on Massive MIMO comes from the increased high speed, tuning the network to help those with the worst service may be more useful.
The ability to tune the beam means you may need fewer towers. As performance at the edge improves, the reach of an existing tower increases. With towers often costing $200,000, even in the emerging world, the savings may bring the effective cost down to a more affordable level.
It's crucial to consider how many will switch off their landlines and go mobile only for data. With LTE speeds often in the hundreds of megabits, the speed is fine for many.
Capacity is the brake on the switch to wireless. Landlines can carry ten times the data, but not everyone needs that. Data caps of 5-10 Gigabytes/months allow only ~two hours/week of quality video. Caps are getting higher, with Free in France proposing 100 gigabytes for $23. That's still below the 200 gigabytes average usage in many countries.
Gigabits are great and an exciting future. Since it takes years to upgrade networks, everything built now should be far more robust than last year's service.
Some people's needs are below average.