The internet has played a huge role in how much ruder this generation is. Anonymity makes people much more willing to say things that they wouldn't say with their name on them, hence the amount of hostility online. Everybody is tougher when they have a computer screen to hide behind.
The further we proceed into future generations, the more behavioral changes that will come with. For example, when my parents were young they followed a strict set of rules and were held accountable for their actions. They were not allowed to speak out of turn or yell at their parents. Today's children have a little less regard for their elders.
In the past even delinquents had a high level of rudeness but it was limited to those that felt they needed to be part of that mindset. Now a days rudeness is not limited to the degenerates it is allowed to flourish among most of the people from all walks of life. Long gone are days when civility ruled as common practice. You would not dream to see people insulting and fighting because a line was too long or someone cut in line. Now this is not to say gripes and voicing complaints is rudeness, but the manor in which you do it determines rudeness all day long. People are more likely to ignore a cry for help today then they were in generations past. People today are more likely to consider those in need as lazy rather than they did in the past.
In certain areas, yes. Some parents don't discipline their children any more (although I would guess that they were probably not disciplined themselves or disciplined too harshly). But I think we just notice the rude kids more simply because they're loud and obnoxious. I work at a summer camp teaching crafts. Each week has different kids. Two particular weeks, one week has the most obnoxious, impatient kids I've worked with (and at a Bible camp!), and the next has the most polite. Point is, there are polite kids out there, but the rude ones are more obvious.
I think that everyone's generation is perceived as being rude, to some degree. After all, even Socrates said that children in his generation were worse than any before him. I think that because all kinds of people raise kids, there are always polite kids and rude kids; I think we just notice the rude ones more.