There are two points here:
There is, in recent years, a definite trend towards nostalgia in numerous products and designs. An obvious example is vinyl discs....it is unarguably easier to use CD's, MP3's and downloads, all with excellent quality. But some (including myself) still like the sound quality and querks of vinyl, and are willing to pay for costly discs and high-end turntables. Why should Kodachrome be different.
And not all photography is about "ultra-accurate" colours (whatever that may be...all our eyes and brains see colour differently). But, if that is the only criteria, why do we bother with B&W, sepia toning, cyanotypes and all the other processes ? And maybe there is also some nostalgia, or at least intellectural or artistic interest in using old processes ? For that matter, why do artists still use paper, paint or coloured pencils, when a digital image is quicker, easier and a more accurate record ?