Yeah, stereo 2-track, so you need a deck that does that too at 15 IPS. But still, they can't manufacture them fast enough for the demand,My very brief excursion into Stereo 8 track was maddening enough, most especially with those interruptive track breaks, sometimes even during a song. I started collecting Open Reel instead and it further drove me insane when the majors, intent on SAVING tape, opted for 3 3/4 ips releases. And of course the best was saved for last .... releasing Dolby b encoded OR 7 1/2 ips tapes as the decks in those days were not exactly S/N ratio champs [unlike those super duper $8K Open Reel Decks of today].
And now Acoustic Sounds and Elusive Disc are offering 15 ips STEREO Open Reels with laser imprinted graphics on metal reels for $450 ~ $600 EACH! Good Luck with THAT!
I've heard them, and they do sound incredibly good.
Then there are 1/4" tapes even better than that, as you might imagine. I have a friend who among other things collects direct recorded tapes, musicians playing straight into a tape recording deck to make just one finished tape in one sitting, and that's the best I've heard from home consumer format tape. Of course the playback machine was an AMPEX MR-70 with a set of heads that alone cost more than a brand new Corvette!