For someone who eats 2600 kcal/day, eating enough protein is very easy, even if the required protein intake for avoiding the loss of muscular mass in old age is significantly greater than 0.8 g/kg.
However, I would not call 2600 kcal/day a value typical for "moderately active" but for an "active" profession.
I work mostly sitting by the computer, but I still walk about a couple of hours per day and I spend about a half of hour daily with more intense exercises with weights, so I would call myself moderately active.
Even so, in most days if I eat above 1800 to 1900 kcal (being a male of average height and about 76 kg), I gain weight immediately. Therefore, for me eating enough proteins without eating too many calories is a problem about which I must think permanently.
Eating only bread is not realistic, but a real diet could include bread made from 250 g of wheat flour + 250 g lentils. This adds to 90 g of protein, but the digestibility of proteins from both cereals and legumes is only about 90%, unlike for animal proteins, so the true protein intake would be 81 g. This would be at the lower limit of an acceptable protein intake for a male of average height, but it would provide almost 1800 kcal.
For myself, that would mean that I could eat absolutely nothing else. Adding the minimum amount of oil to provide essential fatty acids and fat-soluble vitamins would already exceed the amount of calories that I may eat.
If you cook your own food, it is not difficult to have acceptable ratios of protein per calories. However, the food that I see in a supermarket, as ready-to-eat food, almost always has bad or extremely bad protein per calories ratios. If you add a few sweet things to your menu it is very easy to exceed your calories threshold without eating enough protein.