Given that they must have recognized their mortality, they did what they could with what they had to work with. You have to understand, this was something that hadn't really been tried in the same way before.
I sent away years ago for the entire correspondence of Jefferson and Madison (2 -3 volumes). I had a wise old philosophy prof that told me if you really want to know what these kind of people think, their works are ok, but their correspondence really puts ypu in touch with what they think. The prose is beautiful!
I Remain, your most humble and obedient servant my dear Sir,