I would say that generational differences are an almagamation of all of these. In addition, economic differences are responsible for a lot of the changes. My children have grown up with two working parents. This was necessary and acceptable if not expected. When I was growing up, my family was able to exist comfortably with one working parent.
As many have stated above, generational differences are due to a combination of a variety of factors. I will say that some of these factors are more influential than others, and the influence of each factor will still vary to certain degrees depending on the unique circumstances and characteristics of each group of people.
For instance, the generational changes between families of color vs white families, families of the south/rural area vs the north, families of low-income vs high income etc will all have different degrees of changes as their past experiences have also been completely different.
I think every generation is a product of the context in which it is raised and brought up. This explains how we have seen a massive change in the differences between Baby Boomers and Gen Xers. Some are now identifying different trends in the "noughties" (those born in 2000-2010) and Gen Yers have also been catalogued. You can't identify any one factor that produces these generational differences, but it is clear that nurture is a massive factor influencing the values and make up of every generation.
I would agree that all three things you mentioned have had an impact on the changes in generations. The above post makes great points about the changes in education of younger generations. One other thing I would mention is the changing family structure, not only the make up of the family but the changing roles of parents in some cases.
Environment, social situations, religious and social beliefs--all these exert powerful influences upon people. In addition, with the emergence of the television and movies as powerful media and the opportunity for young people to attend colleges in large numbers, attitudes were greatly affected. For the children of the fifties who found their Depression-era parents too restrictive and conservative, the new ideologies taught in colleges by liberal and, at times subversive (Students for a Democratic Society's radical Weathermen--William Ayers, et. al), professors and students greatly affected this generation. Subtle suggestions about racial equality made in films and in some TV shows, new casts, etc. in the later 50s and early 60s also influenced this generation. Then, of course, the integration of races in schools and public places, along with legislation regarding the hiring of minorities, etc. (Civil Rights Act of 1964 and subsequent legislation) certainly affected the demographics of the country, which in turn brought about new dynamics among races.
Because the Baby Boomer generation grew up in an era of economic prosperity, they were indulged; consequently, they indulged their children and materialism became the all-consuming American way of life. And, now technology instructs, as well.
I would say absolutely yes. The environment of the Great Depression and World War II, for example, permanently shaped that generation and gave them values of hard work and frugality that stuck with them their whole lives. The generation raised in the 1950s, by contrast, became used to an affluence that required no such sacrifices, and so their value system and social beliefs were much different.
Are these things mutually exclusive? It doesn't seem that way to me.
For example, younger generations today are less race-conscious than older generations. This could be attributed to more than one of the factors you mention. For example, the change may be because younger people see more media portrayals of people of different races. But why do they see this? It is in part because of changing beliefs.
So I do not think you can separate these things out. Historical climate and changing beliefs go together and both can influence and be influenced by environmental circumstances.