Agreed, seems like overkill to install all dependencies, especially ones that are not compatible with the python version that is being used!
Iām having this issue on a 2 week old installation of hass.io, now updated to 0.55.2
2017-10-18 18:00:11 ERROR (SyncWorker_7) [homeassistant.components.sensor.speedtest] Error executing speedtest: Command '['/usr/bin/python3', '/usr/lib/python3.6/site-packages/speedtest.py', '--simple', '--server', '2229']' returned non-zero exit status 1.
Connect into the container and run the container to see what exit code is return and see what the speedtest script complain about.