I see no way that company would save more money from hiring an experienced developer compared to paying their yearly invoice on the COTS product doing the same thing today. The only way this works is with a very wage suppressing effect.

Off the shelf software could still cost thousands per year and I'm sure they don't do everything the shops need them to do.

Car repair companies won’t see a meaningful improvement to their bottom line with more custom software. Will it increase the number of cars per employee per day they can repair?

I do bespoke work like this, but mostly to replace software that’s starting to cost mid 5 figure amounts per year for a SaaS setup and the support phone line has been replaced by an LLM chat bot.