Los Zetas are in up to their ears in trouble. They're political, business, and trafficking links are all under a ton of pressure and they are losing territory. Further, the way Los Zetas are organized gives a leader a little less say that the way the other organizations are run. On top of that, every other one of the bosses I listed has been a boss for a long time and 42 has only been the boss for a year or so. Don't get me wrong, 42 still runs a powerful cartel and is a powerful drug boss, but I'd put him at 11 on my list.