>they're likely just like you and me, learning on the fly and doing their best

Correct. In my experience of working at a cellphone repair shop, we looked up most Android repairs on iFixit and/or YouTube before quoting a price. If a tutorial suggested that there was a high likelihood of breaking a given part (usually the screen) during the replacement of an unrelated one, we would throw the cost of that part into the initial quote. Apple products are standard enough that the repairs which can be done were well known to everybody, and we didn't have to research those before giving a quote.