[amiga386]

While Admins do have a lot of power, at the same time their power is checked by ArbCom. Admins are held to a higher standard than general users and are kicked out of the role and banned from reapplying if they're found to have abused their privileges (as well as being given topic bans or complete bans from editing).

Merely inactive admins are automatically deadminned, because if you don't need it, you don't get it.

There is also something analogous to the political world: users can petition for an administrator recall, if the issue is a rogue admin abusing their privileges, or even just the admin is trying to hold onto their privileges when it's clear to others that they don't actually need them: https://en.wikipedia.org/wiki/WP:RECALL

So while I don't think Wikipedia is perfect, it does better than your summary implies.