They could spend $75/hr on employees and the cost per car-hour would be just $1.50. That's nothing.
3.5M people work as truck drivers in the US, enough, in principle, to drive ~175M cars at the same time assuming 2% of cars need help at any given moment, ie ~60% of all the cars and trucks in the entire country being driven simultaneously.
Presumably though they'd be able to shave that down a few fold between where they are and dominating transportation nationwide (should they ever do so). So, it's pretty scalable in practical terms.
https://www.census.gov/library/stories/2019/06/america-keeps....
