Samsung isn’t just the best smartphone maker. They make EVERYTHING. Washing machines, air conditioning, laptops etc. If it works on electricity, they make it. They made phones ever since cell reception was available. They made Walkman’s, cd players, boom boxes, home appliances from blenders to dishwashers and ovens and many many more.
They have been in the tech world for so long, in so many areas with so much stuff produced, that they already know what the customers like and want based on what they sell .
And they have plenty of experience with gadgets, and overall technology to make premium smartphones for those who can afford them, but also cheap versions for the financially challenged countries to enjoy without sacrificing their performance.