Teams I've worked on have not had dedicated support staff, but rather engineers rotate 24 hour support duties on a weekly basis.

I have always had mixed feelings about "on call". I dread my turn on the rotation because the imminent threat of a prod issue has a psychological impact on my entire week, even off hours, and usually for a day or two after.

If everybody on the team feels that way, maybe it can act as a forcing function for product quality. I've seen this work on teams that already cultivate a strong sense of ownership.

On the flip side, it really stresses me out, and I sometimes resent that I'm not getting paid overtime for 24hr on call days. Maybe that's just baked into an engineer's salary these days, though...