When your allies die and it's 3v1 under your turret, even as support you have nothing to protect the tower.
There needs to be more items for protecting objectives instead of just killing people or surviving. Objectives are the goal, right? There's even an elixir and dragon buff to help you take them, but Janna is the only champ of the 120 who can do anything to protect a turret with stats instead of fighting.
Erockandroll1 votesJanna's an outlier. But adding effects that are specific to defending objective does not help balance the game. it would make the Early, mid, and late game points less defined, (which would royally screw with the already problematic balancing) Also, Objectives should be easily taken (or at least contestable.) when you have an Un even match up due to a champion death. Kills arn't worth much if you can't turn them into objectives.
And their is are Items for protecting objectives. 
The Ecdysiast1 votes""Hurdur, if you ward you win." You do understand objectives are constantly visible, right?
Tsugaga1 votesThere used to be a fortify spell which made all towers invulnerable and doubled tower attack speed for 7 seconds, it was removed 4 years ago, not sure why it was removed.
RogueWill1 votesWell you have Garrison {{summoner:17}} which does that o Dominion map
The Ecdysiast1 votesBecause all balance choices should be for dominion play.
Variks the Loyal1 votesI had a fantasy where Galio was the 'building protection' champion, as a gargoyle.
He had a new passive that let him perch on top of a tower. His Q had increased spell range, the turret gained a portion of his armor, and he can right click a target to make the turret attack that target. Then he can cast his ultimate down at any point in the turret's range to jump to that position for his ultimate.
qetzel1 votesI think the concern is that games would last too long with a change like this. Stalling is good, up until a point when it gets boring.