mamba
Legend
I’d wager most people are not that interested in high level play, or there would be more demand for it. That also explains why there are few adventures for it (that, and most high level adventures suck)Though there is the everpresent chicken-and-the-egg issue there.
Even if it is just that things fall apart before most groups reach level 15, that still means focusing on 1-12 works great / much better and is not much of a loss to anyone