Lowes and Home Depot are the Wal-Mart of the building stores. That is they only carry volume items, or items that sell fast. Most of these stores do not have any wharehousing so to speak, deliveries are made day and night and stock normally at night.
Small items that move quickly can normally be purchased at these stores for a reasonable price. Where I live, most decent hardware stores (the few we have) close on Sunday. The one that did remain open had their small items marked up from 100-400% over the others. I'm glad a HD did opened up in our town just to force the others to be more competative. But I will agree, the stocking for folks that like to do as we do is poor at best. And the quality of help is normally poor.