They're not soy. We've established that; but a couple points:
If you called them Soy Tacos, NO ONE (except the few of us who know better) would buy them and Jack-In-The-Box would lose money. Most omnis (especially the fast-food crowd) are scared to DEATH of soy.
Soy is added to a lot of beef items to stretch/act as filler. I doubt most people know what a REAL beef taco tastes like anymore.
Not that it's quite the same - but I've fooled (not purposely, just because they never asked) a WHOLE lot of omnis with soy/tvp based tacos.
Most kids I know are even pickier than adults and I've made soy based tacos for my daughter's friends and soccer buddies and not ONE of the kids has ever turned up their nose, or questioned what was in them.
Several have said they want the recipe or "like them better than their Mom's" (or Taco Bell, or wherever) which is probably due to seasoning or whatever.
By now, after making them for years, all the kids know they're soy (or "fake-meat" as they call it) and they don't care in the least, but I've decided commercial places MUST use some soy (though, as we've determined, the products aren't 'all' soy!!) because once you add seasonings, sauce, cheese, toppings, taco shell, etc...the texture seems similar enough for people not to notice.