I sort of agree and disagree with the "essay" format. If only because it is very necessary for life, period. That is probably something as essential as math and that should be drilled into your head as soon as possible and reinforced. A thesis is basically presenting an argument or a point of view, and well, if people can't do that ... well I guess that's what the internet is for these days.
Yeah, I think the process is very rote and mechanical, but you don't want to confuse people by complicating things, obviously. I think the "thesis" structure works fine, it's up to the individual to take it and make it their own. I think the underlying issue is that in high school up to most of undergrad, you don't get to pick your own topics (most of undergrad, you might get lucky) to write about. And depending on how much you want to talk about whatever topic or where you land on the scale of passionate/dispassionate, it's a huge difference to the material that you produce.
Like if I told you to tell me why your favourite movie is the best fucking movie ever, well, you have the tools to do so. Add your enthusiasm for the subject and I'm sure you'll easily blow past the standard 5 paragraph structure but every argument you make will support your overall thesis, and hell, maybe even be convincing (especially if you want to convince me your favourite move is a comic book movie).
It's not strictly limited to the liberal arts either. I assume scientific papers work on the same general (GENERAL) outline with a few changes for scientific method reasons, etc. I never really got past a scientific paper without falling asleep (I have a B.Sc, laugh at me) but it's the same thing: you make your thesis (or hypothesis anyway), then you discuss the methodology, etc, then the results, implications, etc. Seems pretty close to me.
I also sorta use the "thesis" structure to evaluate media. And in the same effect, that's also how I sort of write fiction (in a general sense, because it's not as simple but the underlying intent is all there) Not sure if anyone else does it, but I'm sure they do, just not consciously think about it all the time.