I have no doubt that Apple will likely attempt to sever their dependency on Qualcomm when they make eventually make their own modems (they've made incredible strides with their SoC's under Johny Srouji), but it will still be at least a few years before that will even be a reasonable option.
The complexity of engineering that goes into a high-performance modem is nothing to sneeze at, especially when Qualcomm owns a significant portion of 5G-related patents. Even Intel threw in the towel upon the realization that the capital expenditure wouldn't be worth it, and it would be impossible to compete with Qualcomm profitably (Intel stock actually jumped up accordingly). Qualcomm will continue to collect licensing/royalties from other manufacturers like Huawei as well, and is in an excellent position frankly.