Banks basically don't need to innovate on their hours. If all banks are open similar hours, none of them feel the need to impact their costs by opening longer knowing that it will just force their competitors to do the same and level the playing field again, with everyone (banks not customers) losing out.

Barbers, all the ones I've known in a few UK cities have always had at least a couple of evenings they would open for, if not all evenings (though I generally go during the day anyway). Presumably because there's so many more than there are major banks, and because it's a key decision making factor for consumers - people are more likely to think "I'll get my hair cut at X instead of Z because it's open when I want a haircut" than "I'll bank with X instead of Z because some day I may prefer the opening hours". Not sure if my different experience is based on location or the fact that I generally go to not-cheap places which wouldn't use the term "barbers" to promote themselves.