Meh, for $10 I'm not that concerned. But the hakama does have a label that states it's 100% cotton, and I'm reasonably sure that's what it is, although possibly it has some kind of coating. The pleats aren't permapress, by the way, but as I said, they held remarkably well.
A coating is an excellent possibility. The fabric may have started out as 100% cotton, but "pure" cotton it ain't, otherwise those pleats would NOT have remained through all this.
Meanwhile, in response to the desperate person who contacted me offline per "How do I make permanent press hakama pleats at home???" with offer of firstborn son . . . (Unnecessary! Really!!
If your hak is cotton/polyester blend (10% or more poly is best) lay out your pleats exactly as you want them (this is permanent!) And do a test spot before you start.
-- Steam press pleats smooth and flat.
-- Mix 2 tablespoons white vinegar in a cup of water.
-- Wet the pleat edges with sponge and vinegar solution (I suggest you do each one individually) and steam press dry.
This treatment will NOT work on a cotton hakama. For cotton or hemp, you'll have to return to tradition--stitching your backpleats. Until very recently Japanese fabrics were never more than 13"-14" wide, the width of a hand loom. Thus a hakama was made of multiple panels, the seams between them hidden in the back pleats. And fronts might be stabilized with rice paste.
You can emulate this by topstitching the inside (valley) pleats. Use a narrow zig-zag stitch (a straight stitch will pucker). Just the back half of the pleats "permanentized" will make folding enormously easier. I suspect it might be possible to line the backs of the outside pleats (mountain pleats) with lightweight iron-on polyester stabilizer with the vinegar and steam treatment, but I've never tried it.