I generally expect most retail places to be open starting at 10:00am but honestly I rarely shop at that hour. A more comparable operation to yours that I frequent would my my local homebrew store which does keep some fairly odd hours (12-6 Tue-Sat, closed Sun/Mon) and I have adapted to them. But there aren't exactly major retailers putting pressure on them to have more flexible hours. Only competition they face is from internet sales.
For my restaurants we keep different sets of hours for different days, we stay open later on Fri/Sat and open an hour later Sun mornings, but that is pretty SOP for that industry so consumers are used to the idea. We used to adjust our hours to be open even later during the summer but scrapped that idea about 10 years ago.