2) Is a JLCPcb level of automation something you can put together off the shelf, and if so would it be possible to replicate that process anywhere? Does this only work economical in China?
There are two parts to that automation. One is user facing part and then the actual manufacturing. US manufacturing fails at the first, most likely because they also behind on the second. You don't want to have a slick interface if you can't handle all the orders that come in. And you don't want to build up manufacturing capability if you won't have any orders.
And even if you decide to automate stuff, you would them have to invest in marketing. So, it is a lot of upfront investment.
Just looking at the first US manufacturer that came to mind (4PCB / Advanced Circuits) - go to their site, see big green "GET INSTANT QUOTE" button, press it, observe - "CREATE ACCOUNT (NEW USERS) | LOG-IN". Nope, thank you, the quote was not as instant as I needed it to be. I'm not giving you my email to be spammed before I know I want to deal with you.
And the only reason they came to mind is that I look at their promotional PCB coaster every day. So, clearly they invested a bit into marketing. They just don't seem to get how modern times work and that nobody wants to talk to sales people, except other sales people.
OSH Park are exceptionally good at what they do, but they are really only setup for prototypes. I started using them a lot after they added "after dark" color option. I would not be using puke purple even for prototypes. But unfortunately "after dark" is only available in two layers, no 4 layer option for that. If I were them, I would drop the purple gimmick and revert to the plain green PCBs. They would get a lot more business at least from me.
If anything, for hobby friendly stuff, OSH Park will scale up sooner than any of the established manufacturers.