I was surprised about companion nodes not repeating, but I came to understand why. I was running a repeater and the community gently told me to just turn it off. You can cover the whole city with three repeaters. There are more than three of course, but I was basically not helping anything, I was taking precious airtime.
The repeater nodes are pretty cheap and you need to really think where you put them - as high up as possible, with the best visibility. Most users given this option would be like me "I want to help the network". But I was not really helping, I was just using airtime in an area that was perfectly covered.