No comparison
Your local back street repair person buys the screen glass for about $5 including shipping from Ali Express and does the repair for $80. The $75 margin allows them to cover their costs and make a reasonable living out of it.
<sarcasm - just in case> How dare you. Don't you realise that the fanbois doesn't just want a screen replacement, they demand a genuine Apple screen replacement. Yes they could replace the screen for $30 but it wouldn't then be an Apple iPhone - It would be a cheap knock off because it wasn't 100% Apple and they didn't need to give up their first born as part of the deal to get the new screen. A fanbois would prefer to be hanged, drawn and quartered than be accused of using non-genuine parts or not having a 100% genuine Apple product.</sarcasm>