If the Mexican Church were to work harder to convince the wealthy patrons of the Church that more needs to be done to address the pervasive violence and corruption (like, eg paying civil servants decent wages -- a truly novel idea!), to help the poor and to stabilize the middle class, then, perhaps, there would be far less need for la Santa Muerte.  But, of course, that would involve real work and could involve angering those who have great wealth.  It's far easier to encourage devotion to St. Jude, who is, after all, the patron saint of lost causes.....
Instead of truly working to help people, they are dangling shiny objects to divert peoples' attention.