I think people these days are too awkward to make extended eye contact. They'd rather post a Facebook status and have the other person "like" it than actually make real life human contact. It's safe to say that if anyone makes eye contact for more than 5 seconds, they're worth talking to. Either they like you, or want to hurt you, either way, worth getting to know.
I don't really think such a sweeping generalization could be valid, by dint of its many flaws.
First, you begin with the unfounded assumption that a lack of real-life human interaction causes or may cause difficulty with maintaining eye contact. The degree of one's preoccupation with activities devoid of direct human interaction (e.g., using the Internet, playing video games, texting) may be correlated with the degree of one's social awkwardness or gaucherie. However, which came first: the social crudeness or the obsession with impersonal activities? Social anxiety and many neurodevelopmental disorders are accompanied by an uncomfortability with eye contact and social interaction in general. Perhaps people afflicted with such disorders are more likely to engage in or obsess over these indirect forms of intercommunication than individuals not effected by the disorders. A possible effect of this would be the mistaken assumption that the social crudeness resulted from the social isolation, rather than that the social isolation was a side-effect of the preexisting social crudeness.
Second, you fail to take into consideration the cross-cultural differences in oculesics. In Western culture, people failing to make sustained eye contact are perceived negatively, and are usually considered dishonest, sly, antisocial, untrustworthy, coy, sneaky, unfriendly, disengaged, apathetic, etc. On the other hand, many other cultures regard eye contact as hostile, inappropriate, indecorous, aggressive, lascivious, impolite, invasive, disrespectful, etc. Thus, someone raised within the culture of, say, East Asia should not be judged or evaluated with the same standards as someone brought up within, say, a German or French milieu, insofar as eye contact is concerned.
There are several other flaws I find in your assumption that I think may be too insignificant to mention or discuss in detail. However, I'll comment on them if you'd like.