The New American design aesthetic (“clean lines”, designed in plan view, use of the same materials, including planting, regardless of locality) delivers one thing extraordinarily well: convenience. More efficient parking, less maintenance, faster routes to, and through, a place, faster installation, quicker design process, etc.
This focus on convenience is probably an outgrowth of the desire to “simplify”, or not have to think about, aspects of our lives like transportation, food, technology, and entertainment. The less time we spend thinking, the better (or so we’re told).
It also removes the possibility of being different, and having to explain that difference to a friend or family member, who might frown at the non-conformity (see Nice vs Good).  For public spaces, this effect is heightened by real or perceived political pressures.
So, staying the same, and making everything new look the same, are convenient. They also reward the part of our brain that revels in knowing that we made the decision that is looked upon positively by the group. Seth Godin calls it the Lizard Brain, and Stephen Pressfield calls it the Resistance.
On the flip side, making design decisions based on what you think is right, what will be best for the site, it’s users, and contribute more fully to its environmental context, may be the least convenient thing you can do – from many angles. But, it’s what needs to happen.
It’s also what separates the good design professionals from the bullshit imposters.