I'm not sure what fundamental characteristic of Americans would make them significantly different then the overall population of the earth in terms of planning.
Americans, both people and companies, are much more short term focused then, lets say Germans or Nordic countries in Europe.
And again, no comparison with let's say China. A government in China may not only make a 5 year plan, but a 50, 100, 150 year plan. This may look mind puzzling to you and you can doubt it's effectiveness. But nevertheless they do.
It is said that Deng said, when asked what he thinks about the French revolution (1789!): "It is to early to tell"
We've all been raised on television to believe that one day we'd all be millionaires, and movie gods, and rock stars.
Sure you need wealth to pass it on, but notice how you limited you statement to wealth, that is why American's are IMO different than the overall population of the Earth in terms of planning. I think other cultures are more in touch with reality and not so consumed with wealth. The reality is even if you die with no wealth to pass on, you have a body (what is to be done with it?); you may have minor children (who do you want to be their guardian?); and you may not die but simply be incapacitated (who will make your health care decisions and what do you want those decisions to be?).
The average American has a weaker social network than people from other countries. Americans are also highly focused on consumption and status symbols - more than people from Russia or China.
Systemic economic reasons seem more likely. I'd note that you have to have wealth to pass it on, and that economic mobility in America has been in decline since the 80s, https://www.theatlantic.com/business/archive/2016/07/social-...