You don't suck. You are doing good by them by staying out of the way. Most people are not children and don't need scheduled pampering after initially. There are other ways of making oneself available which is all that is needed. The other people here who have endless meetings are doing nothing but looking out for themselves (see example where they don't want their reports to leave, therefore must keep tabs on their feelings for themselves). Can't blame them but let's also not kid ourselves that that is being a "good manager" for reports.

If your team is functioning well, there's no need to change. You can do what my manager does...who also has 15 direct reports and largely tries to get out of our way. Block off two hours per week. One hour per day. Anyone on your team can schedule a 1:1. Most weeks, probably on one will talk to you. But if someone has something to discuss, they can just place an invite on your calendar.