What's with all these kill lanes?

All of a sudden I'm noticing people are opting for kill lane duo mages bot lane now rather than adc/support bot lane. I know this is because adc's were nerfed in this last patch...BUT, late game wise, doesn't it make more sense to play an adc who's dmg is dependent on their auto's opposed to their abilities?

Just getting real annoyed playing mf against veigar and xerath bot lane when I could've taken syndra and whomped on both of them throughout the laning phase...Late game is easier because if either of them do carry, it's not as hard to take them out but, It's just fkn annoying early game. lol.

It just makes little sense Imo, because an adc can continuously and noticeably get stronger with every back whereas a mage takes longer to build up their ap/dmg. I feel like people are taking the combo because it's 'easier' but in all reality, it puts their team behind because they don't have a dps champ.