This is not and advancement in technology, my current phone can connect to Bluetooth headphones AND standard ones as well.
and detriments as is being pointed out. (Though it is not an advance)
This is argument is odd, it’s coming off as coming from the manufacturer’s perspective instead of a disinterested third party, the use of the phrase “your particular use case” seems to suggest that this use case is limited to a single user or a small subset of users which is not my experience.
The fact that these acommodations are cumbersome is the whole problem of course, manufacturers make the phone marginally smaller by offloading a feature to a dongle that takes up far more space than is saved.
Your use of stagnant here is interesting, because if I’m forced to think about it, keeping the headphone jack on phones only seems to lead to one sort of stagnation and no other and that is economic stagnation, the need to continue the endless upgrade cycle on phones cannot continue if all phones can do anything, so they must always be different even if that difference is meaningless, shaving millimeters off, making the screen so big it doesn’t fit on the phone ( the “notch”) and other meaningless changes that at least distinguish the phone as newer and therefore better because “technology advances”.
These days, “getting with the times” means pushing back instead of passively accepting what our corporate overlords push on us as our own desires. Stagnancy comes from uncritically accepting business plans designed to extract wealth as the way of the future.
I don’t generally disagree with your conclusion, that is, you’re not way off. Manufacturers do in fact make dozens of models with a lot of hardware permutations, and they do this to try and sell a phone to everybody, flagships are there to extract money from people that have it and cause envy in people that don’t. Doesn’t matter that they can’t afford the features they want now, but when the next round of midrange phones trickles down a couple of previously unavailable features in that price range, they too can upgrade to the features they lust want.