Ambition: Why isn't everyone ambitious?
Lack of self-efficacy.
Turn on the TV or read the news and you are presented with this reality:
"Here's some people doing a lot better than me in life, in every imaginable sense."
Most people respond with this thought:
"I don't have the means to do the things required to achieve the best version of life I've seen, so instead I'll marginalize any value judgement of what a better life is using the excuse of relativism/subjectivism."
Part of the problem is that we have a strong campaign, even here on Quora, by people that would like to wash away any level of objectivism in defining what a good life is, or by admitting that some people live better lives than others. While there are both subjective and objective elements to the definition of a good life, making the argument that it is entirely subjective is foolish and destructive to human progress.
It should never be uncomfortable for someone to say "I think people should be more ambitious!" That's an entirely positive statement, and it starts with an acknowledgement that people do have different levels of ambition. But what's most important is to acknowledge that ambition isn't just some neutral value, it can be a great thing, and it's worth striving for.