I disagree. The industry is pushing users towards wireless headphones. Although no phone is currently thinner than the 3.5mm jack allows, transitioning users towards wireless audio sets them up nicely for the transition when the phones do get thinner. the dongles are for bckward compatibility with the wired headphone users.
Nothing of what you said invalidates amirm's statement. Which is that the decision to remove the jack is anti-consumer. And it is. Using wireless headphones was always an alternative. But with the removal of the jack, we are more or less forced to go wireless (dongles often stop working, and they also are very easy to lose, and are just annoying to deal with, for a lot of people; Apple have already stopped providing dongles in their boxes as well).
As for the argument of thinness, you simply have no leg to stand on. Current phones are around 8mm thick -- in fact, phones got thicker on average after removing the 3.5mm jacks (as it was around the same time bezels got smaller, which for obvious reasons necessitates increased thickness) -- to compare, iPhone 6 and Galaxy S6 were substantially thinner than the iPhone Xs and Galaxy S9 today. Furthermore, some of the thinnest smartphones ever made, like Vivo X5Max (5.1mm), come with a headphone jack.
So we are far and away from any realistic, foreseeable future of smartphones becoming so thin that 3.5mm can't fit. As for your reasoning that this is setting up "for the transition when the phones do get thinner", that's just an unconvincing argument. How is it more justified to do that "transition" now, rather than later, when we get to that point (supposing we will ever get to such a point)? Also, wouldn't continuing to sell wireless earbuds, and improving on them and their technology (BT is still a mess in many ways), all the while keeping the 3.5mm jack until users willingly go over, be a more rational transition?
This isn't a question of wireless or wired. It's a question of choice. A very, simple, fundamental principle that anybody can understand. Before they removed the headphone jack, consumers had the choice between BT and wired. Because of huge price increase of BT, the unimpressive battery life (and extra work that comes with charging them), the imperfect technology of BT (connection issues, drop-outs, latency problems, so on and so forth), as well inferior SQ, users stuck by wired.
Any rational analysis would tell you that the best way to move users over to wireless would have been to refine and improve the technology in the areas I just mentioned. But OEMs went the other way; by removing the 3.5mm jack and forcing us over. This fact cannot be ignored.
It just beats me how radically pro-corporate some consumers are. They literally accept the explanations given to them by various corporations (in this case the smartphone OEMs) the same way citizens in a totalitarian states does from its state; without critical analysis or thought, and always rationalizing their actions -- even when bad. Which makes sense, seeing as we live in a highly totalitarian culture. And corporations have totalitarian structures as well, internally. There is also no doubt some of the attitudes consumers have of various companies, in particular in the smartphone industry, is similar in this sense (that's where you get descriptions like "Apple sheep").