Fairy Tail vs Alvarez Empire

Just thinking that a small guild like Fairy Tail is taking down an entire kingdom all by themselves and the Springgan 12 are considered to be equally strong as God Serena who was formerly the strongest in Ishigar are being taken down fairy tail wizards. It is always fairy tail alone doing all the job and making them OP every single arc. Why can't other guilds be involved in fights. I want to see wizards from other guilds to get more action and make a name for themselves other than fairy tail getting all the credit and how can Acnologia get involved in this war.