Apple depends on Qualcomm just like everyone else (except for the new iPhone Air)... so this really doesn't seem like a valid excuse for Android manufacturers.

They don't though (also the 16e has in-house apple modem, I have no idea what the fate of the intel modems was). The majority of other vendors' designs get full qualcomm soc's with dsp, modem, security processor firmwares.

Apple literally has the scale to go to Qualcomm and buy slightly customized variants (the X71, for instance). And those modems are integrated with their custom Apple designed chips. I don't see any other vendor able to do that.