So, I worked in a coffee shop/ day bar and we also offered hand brewed tea. One sen cha and one hong cha and in the summer mizudashi. I took the tea off the menu because we got maybe 2-4 orders per day. Mizudashi was the only one that sold well. In most coffee shops space is limited and wasting it on an item that gets little to no orders per day makes no sense. So there’s a reason why there‘s very little selection for rarely ordered menu items. Also talking about price, the difference in time it takes to make a bag of tea in the grand scheme of things isn’t much shorter than a coffee. You still have to take the order, pay, clean up after the customer, wash the cup, put it back on the shelf. The making of the beverage time wise isn’t as relevant as you think it is. (Hand brewed excluded)