This "volume of work" is very interesting.
Time and time again, I contact some avionics shop about some work, and they always say they are inundated and can't do it for the next 3 weeks.
When I finally get there, I see 1 person walking around, another slowly wiring up some connector in an equipment rack, and not a lot else going on.
Something doesn't add up here. Somehow these firms regularly go out of business, despite constantly quoting long lead times for new work as if they were inundated with work. And avionics work is hardly competitive - the trade margins on the supply are very generous indeed for example.
The actual hourly rates in GA maintenance are not at all high; in fact they are usually lower than garages.