As people are buying phone mostly in price range of midrange and upper midrange they prefer
Design.
And, contents inside the box.
If the brand starts to give these two basic feature, I think most customers of another smartphones are tired of using their ui and will attract towards the greatness i.e OneUI.
Greatest example is the motorola with great looks and design it is changing the shape of midrange market especially in market like india.
Motorola's camera and audio department need a quantum improvement. Most people buy phones looking for the best in these two departments. I phone excels in camera which I must admit being a Samsung user.
Samsung Software is designed to compete to best so i don't doubt on that because even in budget devices it excels the camera and other software tricks.
