Because they US has been systemically constructed to funnel wealth specifically to white men. There are a lot of papers out there that discuss the history, reasoning, mechanics, etc of the whole thing, and why it is important. These papers are easy to find, if you actually want to know.

The fact that you think staying on subject is important here because the subject is the US, and not some other subject, is stupid. You can, physically, talk about anything, at any time. However, if you wander into a conversation about one group, doing a thing, and start interjecting talking points about another group, you are just being an asshole, at worse, or very unaware of how conversation is generally held, at best. I also never implied it was due to lack time. I have implied it was due to lack of desire to do the work, especially when that work has already been done, and is readily available online, by people who are experts in the subject matter.