We've rented from Turo several times, but only in super-touristy places -- Oahu, Napa, etc. Average cost per day for an SUV was around $75-$120. If they rented 20 days a month, those owners were making $1,500 to $2,400.
All the cars we rented were late models and really nice. So I'm guessing they are used solely for Turo.