I agree with internet but also media, playing a ginormous role in terms of teens showing lack of empathy. For example, constant glamorisation of infamous scum such as school shooters have caused many students in America to feel de-sensitised. We saw an example of this in the recent school shooting where one student wasn't surprised at all. Such constant streaming and glamorisation of destruction, violence and the dark things of this world make us feel like it is the norm.
In addition to this, I think the lack of role models due to such negative conditioning is what is changing the attitudes of teens also. Recently, we have seen a huge surge in teens that disrespect their parents (for e.g. cashmeoutside girl, lil tay, almost every teen on that Phil show) and the audience seem to applause and find their disrespect funny and entertaining. We find memes that whilst mocking them, sometimes glamorise such people. Essentially, parents who are bad role models, are using their children as a hate sponge-as a means to make money- and such attitude is reflected through the children, who will discard respect, who will discard rational thought, who will discard empathetic feelings and the ability to understand why parents feel upset and angry when him/herself is entirely responsible and instead adopt an attitude where 'money=happiness'. Money making machines.