Just like they've been waiting for the past two years? Now was the time for Tesla to make the shift if they were going to (while they were retooling the lines). They didn't. Show of hands, who thinks they'll be taking down the lines yet again the day after tomorrow, to use cells that they have a shortage of (2170s) and not use cells that they have in surplus (18650s), both of which have the same energy density (as measured by Jack Rickard)?
There's simply no logic in it. As has been repeatedly pointed out.
The next thing that might be seen along these lines - not soon - is a change in the pack (not cell) architecture. But again, to reiterate: not soon. Now was the time for that if they were going to do it. Next up on the list is surely interior cosmetic features - which might well be phased in one at a time rather than all bundled together. There's little line downtime for such changes - they're GA, humans connecting the new part rather than the old one. More of a supplier headache than a Tesla headache (excepting parts made inhouse).