To begin with, these overseers were all anointed Christian men. At Revelation 1:16, 20, those who served on bodies of elders within the anointed congregation were symbolized by "stars" or "angels" in Christ's right hand, that is, under his control. In this time of the end, however, with the number of anointed overseers still on earth ever dwindling, the vast majority of Christian elders in the congregations are of the other sheep.
Sounds like Jesus needed a lesson in inventory control - just at the worst possible time (of the end) he runs out of anointed and has to use the inferior 'other sheep' for the top jobs. Damn! I hate when that happens! It's like inviting everybody over for dinner and running out of roast beef so you have to serve 'em peanut butter sandwiches instead.