I think Millionaire more or less inspired the money trees on shows, but there was still more of a competitive element with the other shows that premiered that season (Greed, 21, Winning Lines, et al). I agree that the other annoying elements (one vs. the house, pregnant pauses, loud family members) were more from D/ND. I actually liked Millionaire's "relationship chair"...it added a nice personal element to the show, esp. when a big winner would celebrate with family.
And honestly, even though they seemed a little formulaic at the time, I actually really enjoyed the shows from 1999-2000, although it seems they all went out of their way to one-up each other in setting the highest winnings record. I think 21 and Greed broke a record within the same week.
The D/ND-esque shows from 2005-c. 2008 (esp. Ende-maul's lot) damn near turned me off from the genre.
/And yeah, I did forget the aluminum girders all over the damn place :-P