I agree with you.You make some thought-provoking points pertaining to the many opportunities for a good drink.
I cannot speak for the OP, but I feel the afternoon is an especially under-utilized time for imbibing. Evenings and nights are already quite popular occasions for such activity. In the morning, I personally do not always feel like having a drink or indeed being awake at all. But the afternoon? I can see no good reason not to drink.
To echo my thoughts above, I think we can all aspire to drink more in the afternoon.
Moreover, drinking in the morning may reveal some problems.
The exception may be something drank in the mornings in the Bolivian countryside made with fresh milk yield and singani (similar to pisco), called leche de tigre (not to be confused with the Peruvian stuff).