User blog comment:AdmiralPedro1stFleet/How to Explain Absence of Geth Juggernaut and Geth Hoppers/@comment-1900300-20120303022139

Well duh. Geth design all their platforms, constantly shifting their programs to the platform they need. If the find a platform is not suitable to the mission at hand they simply move their programs to a different one and use that. They probly have hopper and Juggernaut platforms but they didnt suit the sitations the geth faced, or yes the geth found them unreliable and recyled them to other platforms