Does anyone pre-juice their fruit juice for sale?
There are.  There was a story on a local station about JRINK when they hit some anniversary a year or so ago.  (It might've also been about the owners ... being successful female, minority millenials)
They're doing some sort of 'single page app' thing on their website, so I can't link straight to their about page  or FAQ, but it confirms that they're juicing &amp; bottling.  (so people can do the 'grab and go' thing) :

Why We're Different
...

Locally made every night, we delivery [sic] straight to your door and our stores daily.


...

How long will JRINKs last?
Because they are raw and cold-pressed, JRINKs will last up to 5 days if refrigerated and unopened.  Nut milks are ~3 days due to the fatty acid component, leading to higher rates of oxidization.  If you drink more than 2 a day, we suggest waiting at least 2-3 hours between each JRINK.  Once opened, please consume within the next 3 hours.  All our juices are date labeled upon producing and we ask that you JRINK responsibly (i.e. keep them cold!).

I have no idea what their process is, nor what the quality is ... I just know that it exists, and their model seems to be successful for the market they're in.