All of the big companies know that most people aren't willing to base their purchase on whether or not a phone has a headphone jack, and therefore they don't have much to lose from ditching it. They can use that space for more battery or for whatever else they want to put there. The inside of a modern smartphone is a pretty space constrained place.

Buying 6 dongles would also only cost $54 ($9 each) which isn't a ridiculous price for an accessory in my opinion, especially if you're buying a high end phone that's going to cost you $700+ anyways.

Personally, I just carry one dongle attached to my keychain and keep one in the car. It hasn't been an issue for me yet.