Originally Posted by NCC-73515
Why would Vulcan, Andoria, Tellar and Alpha Centauri give up their fleets and let Earth's Starfleet handle everything?
You're not getting it!! Starfleet was probably the best organized and best able to readily assume the lead role. After time, Starfleet became larger as the other planets contributed to it's growth, both through manpower and raw resources. The command structure and ship design remained recognizable even with the addition of alien technology from the other member planets.
Please don't mention Alpha Centauri, nothing written about Alpha centauri has become canon onscreen. Were there aliens or was it just an early Earth colony that sought independance? Depends on which book you read.