Seriously, that seems to be the extent of the logic some of the manufacturers use. Apple has/had an obsession with thin, Apple did well, therefore we need to have an obsession with thin.
Personally, I say fuck that. Phones have gotten anywhere from thin enough to too thin. I had a Note 3 for a few years, which I was completely fine with in terms of thickness. However I recently got an LG G5 which is just slightly thicker, and I actually like it better. The slight extra thickness, combined with rounded edged, makes it really comfortable to hold. Of all the smartphones I've had it fits in my hand the very best. I think they've got it pretty close to perfect in therms of thickness.
Oh and it manages to have a removable battery, headphone jack, and SD card so that's nice as well.
I get annoyed with the worship of the cult of thin. I understand the interest back in the day, I had an early Windows CE smartphone which was a massive brick and ya, I wanted something smaller. However we have gotten to the point where they are plenty thin enough and going thinner is less ergonomic, not more.