I think it depends on the size of the org. If there are only 1-5 devs, then yes, they would be doing the devops. But in OPs case, he is managing the infra for 7

I think it depends on the size of the org. If there are only 1-5 devs, then yes, they would be doing the devops. But in OPs case, he is managing the infra for 70 engineers, there needs to be some formality in place, otherwise everything will spin out of control, if every engineer rolls his own server there that would quickly lead to chaos.