Once you have a good amount of users testing, its not that difficult to get free servers from the ISPs. The secret is that on-net servers show testers better performance than off-net so every ISP wants to contribute the speed test server. If they dont do it they are shooting themselves in the foot by routing their traffic to competitor networks and getting test results behind their peers.
Whats even worst then your competitors can claim awards for the Fastest ISP and your marketing people are furious!
I am not sure why this old news is surfacing here today but I can give my 2 cents, since I sold speedchecker.com last year and were directly competing with Ookla.
The main business is selling the data. You use Speedtest.net to troubleshoot your connection but metrics captured with the test alongside location data give telcos invaluable insights on where they should improve their networks. Telcos pay 6 figures annually for this data and we have a few hundreds of of those big MNOs globally. This market is pretty big. Accenture is in trouble with their main consulting business due to AI so acquiring data business is one of the smart strategies they can implement to stay relevant.
To all commenters who think they can code it over the weekend, yes you are right. I coded my first speed checker over the weekend in 2008 but it took me 18 years to grow the user base , figure out entreprise sales strategy and exit. Its not easy as it seems.
You can already run any workloads on it at a fraction of a price of traditional cloud services.