When Apple released the iMac without a floppy drive, the floppy disk drive was still a universal standard in use around the world everyday. Apple replaced it with nothing. There was no way to write a file to anything built-into the computer for mobile distribution. But it wasn't about whether or not the days of the floppy drive were numbered, or even about whether there was space inside (though it did affect the design), it was about moving people to the internet -- the only way people could move files without adding anything external, and it was over slow, buggy dial up modems. It also cemented the CD-ROM as a software distribution standard. It was also about adding less expensive peripherals to the iMac via USB and making it a standard. When the iMac debuted there were only two USB products available with drivers for the Mac. A printer and a floppy drive, and both were expensive, buggy and hard to get. But because Apple created demand, competition increased, quality and innovation improved, and prices fell, so much so that four years later, Apple finally added a CD-RW as part of the cost of the iMac -- the first re-writable removable media included with the iMac since they dropped the floppy.
You may disagree, but based on every standard Apple has dropped, the same cycle of progress follows, and I contend that as long as the 3.5mm jack remains an option on the Apple products, there will be little incentive for developers to improve wireless technology. And that's why Apple won't include a 3.5mm adapter either. But, the only trade off for die hard 3.5mm legacy equipment users is that they have to use a simple adapter.