Unclear, but probably incorrect.So they couldn't figure out how to make their own 5G modem and had to go crawling back to Broadcom.
First Broadcom doesn't sell 5G modems. So...
Second the announcement is very specific that what's being bought are very specific components (think things like filters or RF power amplifiers). I don't want to say that these are trivial components, more that they are natural boundaries at which to reduce the size of a modem project. You could draw an analogy with something like the PMIC; for years this was a third party component (even though obviously Apple cares an awful lot about power management on iPhone). The main issue was simply priorities; the payoff from controlling the PMIC was lower than the payoff from Apple designing other elements of the iPhone, right up until all those other elements were part of the internal Apple iPhone project.
Same thing here. At some point Apple may design their own filters, RF amplifiers, etc; but that's just not a tier one priority for the modem project.
If this were some random deal with a Japanese or Taiwanese company it would not get any sort of announcement. The only part that matters is that both Apple and Broadcom see favorable political PR in announcing that at least this (small) part of future iPhones will be made in the US (for at least a few years).