My back garden is quite a big one for a suburban semi. I have not cut the grass all summer. I have a self-seeded buddleia, other blossoming shrubs, and as many trees as my garden can support, including a self- seeded oak.
My front garden/drive is gravelled (with no weed suppressing membrane), and has a good covering of grass and various wild plants.
Most, if not all , my neighbours have tidy gardens. That is a large cause of no bees. However the main cause is agribusiness that sells pesticides.