There are two flaws in your logic. First, if your
adminship bit is
removed, how do you "unblock" yourself? So no, you don't need an extra
"super-admin" level to do de-sysoppings, you can just allow admins to do
it. Second, your argument would equally apply to page deletion (you can
publish any crap because if anyone deletes it you can just undelete
it!), and yet admins can all delete *and* undelete and it still works
(because they largely follow a certain policy).
So not only do you want to make everyone admins, you want to make
everyone stewards? If anyone can desysop anyone else, then all it
takes is one bot to remove everyone's sysop bits, and we have to wait
for a dev, or steward, or whatever rank is high enough to avoid the
bot's grasp, to revert it (which could be made quite easy, but it
could be a significant wait until someone is available to do it). The
cleanup of the damage the bot has done in this time (or, probably
multiple bots to make it harder to undo) couldn't start until this dev
had been found.
Whatever way you look at it, you're going to need a significant number
of people with greater powers than everyone else, it's unavoidable. At
what level of power you draw the line can change, but you still have
to draw the line somewhere, and wherever that is, you'll have the same
problems with selection.