At the time of his analysis, the Helium network had about 39,000 hotspots with about 32.5 million data credits spent in 30 days by network customers for data transport. At the fixed price of $0.00001 per data credit, that customers spent a total of $325. On average, each hotspot earned a little over 8/10 of a cent from data traffic during those 30 days.
In the 14 months since that analysis, Helium signed up many more data customers and grew the network to almost 920,000 hotspots. Customers spent about 187 billion data credits in the past 30 days at a total cost of $1.87 million. On average, each hotspot earned about $2 from data traffic during the past 30 days.
Hotspot owners also earn rewards from proof of coverage activity: sending beacon messages and witnessing those messages from other hotspots. Proof of coverage rewards were very lucrative during Helium's first year, but diminished rapidly as more hotspots shared proof of coverage pie. Those rewards also diminished in urban and suburban areas as people deployed other hotspots nearby.
The Helium Explorer [2] lets hotspot owners find locations where proof of coverage earnings remain high. These locations are in smaller communities and on the periphery of overdeveloped metropolitan hotspot clusters.
[1] https://youtu.be/nerQCrOam5U [2] https://explorer.helium.com/