Thoughts in the car:
I just had a discussion with a coworker who bemoans the lack of respect and responsibility of the newer generations. While I do think these concerns are typically overstated due to availability bias, there could be some truth to them.
I hypothesize that a significant contributing factor is our ever-expanding population; our increasing ability to discard one social group and easily form a new one. One of our primary motivations for being kind to others is the hope that others will be kind to us. (see the thought experiment 'Prisoner's Dilemma') Yes, most of us have empathy as well, but this can vary by degree and situation; the most reliable motivations are usually the selfish ones. If we are able to exploit one social group, then move on to a new group, thereby avoiding the consequences of our actions, this encourages exploitation ("exploitation" is defined here as reaping the benefits of a social group while not respecting others or taking responsibility for your part in the group). Side note: A lack of consequences for our actions is also an explanation for why internet communications can so easily turn toxic.
Before we can falsify this, we would have to first establish quantifiable data to represent our culture of exploitation. Then we could demonstrate a similar environment (large choice of social groups) where such a culture of exploitation (among relatively equal members) doesn't occur. Or, we could find a culture where there ISN'T a large choice of social groups, where exploitation (among relatively equal members) occurs regularly. Finally, we could identify a different factor that better explains the data.