Yup, think there is a going to be a lot that will have to weigh up the cost of opening vs the profit or lossI think they are chancing on the definition of garden to get the figure that high tbh. Most pubs will be in high pop density areas where space is at a premium. Back in my neighbourhood in England I can think of only three out of nine establishments locally that have a beer garden, ones ok , another is small with plastic grass and took about 15 people pre covid and the other is in a car park. Oh and theres one with a rooftop terrace overlooking peoples back gardens and an alleyway. Theres loads with smoking areas but they are tiny.
Opening/reopening a pub is a very expensive business, especially if doing food as well.