I think it stems from a lack of design DNA in our culture.
We allow traffic engineers and horticulturists to determine the look of our city yet neither are design-trained.
Or if we do hand over the project to the design professionals - landscape architects - we increasingly find they have abandoned their roots and become ecologists in order to please their clients.
This is wrong. Landscape Architects are the people entrusted with the design of our public spaces. If they abdicate this responsibility in order to ensure their projects have smooth passage across local government desks, who's looking out for the aesthetics and functionality that actually make a place liveable?
What to do? Teach design in our schools from a young age (it's as important as literacy and numeracy) and gradually we'll build a culture that sees good design as normal and expects it. Like the Scandinavians. When you go there and see that all their taxis are Saabs and Volvos, you realise that this is a people who are immersed in good design all day long and simply don't accept poor-quality things that don't work.
We need to get to this place too.
* When you're design-trained, you realise that there are certain non-negotiables and that's why everybody does them. When you insist on difference simply for difference's sake, you run the risk of transgressing these rules and creating things that don't function.