Why aren't more people interested in Dhamma? I read somewhere that Dhamma should only be taught to people who are interested and attentive to the knowledge, but why aren't more people interested in the first place? Dhamma could lead to the end of suffering, which is something most people would be interested in right?

Is this because of indifference and thus ill-will and aversion? Is it because of delusion? Laziness and lethargy, or other parts of the five hindrances? 

And why do people react so hostile when discussing achievements such as having better concentration, more equanimity etc.? Why don't they see it as an opportunity to learn something new? Why is there such a lack of enthusiasm and a drive to search for wisdom?
In the Ayacana Sutta (SN 6.1), the Buddha explained that for the masses who are strongly clinging to sensual pleasures and other things like name, fame, wealth, health, relationships etc., it is hard to understand the full depth and breadth of the Dhamma.


  Then, while he was alone and in seclusion, this line of thinking
  arose in his awareness: "This Dhamma that I have attained is deep,
  hard to see, hard to realize, peaceful, refined, beyond the scope of
  conjecture, subtle, to-be-experienced by the wise. But this generation
  delights in attachment, is excited by attachment, enjoys attachment.
  For a generation delighting in attachment, excited by attachment,
  enjoying attachment, this/that conditionality and dependent co-arising
  are hard to see. This state, too, is hard to see: the resolution of
  all fabrications, the relinquishment of all acquisitions, the ending
  of craving; dispassion; cessation; Unbinding. And if I were to teach
  the Dhamma and if others would not understand me, that would be
  tiresome for me, troublesome for me."


And then, most terrifyingly to us:


  As the Blessed One reflected thus, his mind inclined to dwelling at ease, not to teaching the Dhamma.


Fortunately the Buddha was persuaded otherwise:


  There are beings with little dust in their eyes who are falling away because they do not hear the Dhamma. There will be those who will understand the Dhamma.