Why are high-end smart door locks

Why are high-end smart door locks "not selling"? After reading the negative reviews from netizens, I suddenly understood

What is the difference between smart door locks with a value of over a thousand, over three thousand, and over five thousand?Although it's a 'one price, one good' approach, there is also a cost performance factor to consider. The sales of over 5000 smart door locks are the lowest on various platforms, but they are the most popular mid range products of over 3000...