Can we manufacture touch screens at scale?
Can we manufacture Li-ion batteries at scale? (Tesla and Panasonic might be able to, with large new investments, but I don't think there's anybody ready to go)
Do we have 3nm fab capacity? (TSMC is planning to build one, but AFAIK not yet)
Do we have the ability to manufacture various sensors at scale? (Some likely yes - ambient light, inertial - some no)
What about image sensors? (Maybe, Omnivision is probably the best candidate, but I don't think they can currently do 48MP. ON Semiconductor is also a good chunk away from that, AFAIK)
I think that's a sufficient number of parts to claim we currently can't make cell phones, as long as you define cell phone as "current gen cell phone". We could probably retool relatively quickly back to at least cell phones, but even that is AFAIK not a current capacity.
Can we _theoretically_ do all that? Sure. But we can't right now, or within short time frames, and we can't without significant investment.