Quoted from Pinballomatic:
2016 saw the addition of the second playfield line to allow WOZ to go on without tying up the main line. At the time it was to not interfere with Hobbit; today it's to not interfere with DI. So that helps.
From what I read, they mothballed the dedicated second line, at least temporarily, or converted it back to DI. They couldn't keep up with DI orders so were only producing them for at least a couple of months AFAIK.
Maybe they can shift a lot of storage off site or into an adjacent building, and increase the size of the lines ... but it seemed to me like they were struggling to keep up. Pressure's likely to increase with #4 and #5.
Either way, I'm pretty certain earlier predictions about Stern having less than 50% of the market of new, shipping machines by the end of this year will be correct. Might be well under, given the numbers CGC appear to be producing.