>>112602869They started doing this in the 1980s and 1990s when X-Men sold better than anything else. They kept doing it in the 2000s after X-Men stopped selling so well. When they finally cut the line down in 2015 it was a long overdue reaction to the franchise's decline, but Ike's agenda about movie rights became known so everyone pretends it wasn't still a sensible business decision to scale down. Marvel tried to appease angry fans by launching more new X-books than anyone needed, and most of them still sold badly, the Age of X-Man event was a disaster, and all the ongoing X-books except UXM were outside the top 100. They finally had a success with HoXPoX, which sold like an Event.
Now they've launched 6 new books, stores ordered high on the first issues of them all, but only the main X-Men book kept the sales up for #2. If that trend continues, Marvel are vastly overestimating demand by launching so many X-Men books, when readers just want the one Hickman book.