Isn't zhonyas crowding out other items in its class ?

In a discussion about tytanic hydra one rioter answered to my question (senpai noticed me) about giving tytanic hydra the old atmas passive

his answer said that they dont want to make this item a good fit on a broad pool of champions because it will crow out other item purchases across the board

but then it hit me that when it comes to defense on a mage ... there isnt really any other option that matches zhonyas

zhonyas is great ... it gives you a solid defense from people who hunt mages ... all while also giving you a serious ap injection to keep your offense top tier the item itself isnt op ... the active can backfire ... but comparing it to either full defense items or other defense/ap items ... noone comes close and zhonya is a staple item that does all the defense mage usually needs

isnt that something that a problem in itself ?