I've seen too much data and analysis that proves, at least going by the NBA seasons we have to draw from, that the best way to maximize championship potential is with a top 5 player.
http://www.82games.com/dennis.htm
Just read through the article above to refresh a few points on the question. The data only goes up to 2005, but the patterns still hold. A few noteworthy stats:
92% of NBA Champions had a recent All-NBA 1st Team Selection
81% of NBA Champions had a recent All-Defensive 1st Team Selection
92% of NBA Champions had a Player Ranked in the Top 8 in Efficiency the Preceding Season
No NBA team has won a championship without a Top 5 player or Top 5 defender
So yes, I am a big believer in the superstar theory, though there's always the potential for exceptions. And, not surprisingly by design, the best way to acquire one of those with a good chance to keep them around is through the draft.
2012-13 - Miami Heat. LeBron James = #1 RS, #2 PS
2011-12 - Miami Heat. LeBron James = #1 RS, #1 PS
2010-11 - Mavericks. Dirk Nowitzki = #10 RS, #5 PS
2009-10 - Lakers. Pau Gasol = #5 RS, #5 PS (Kobe #6 PS)
2008-09 - Lakers. Pau Gasol = #7 RS (Kobe #10 RS), #7 PS (Kobe #4 PS)
2007-08 - Celtics. Kevin Garnett = #9 RS, #7 PS
2006-07 - Spurs. Tim Duncan = #9 RS, #5 PS
2005-06 - Heat. Dwayne Wade = #7 RS, #6 PS
2004-05 - Spurs. Tim Duncan = #6 RS, #6 PS
2003-04 - Pistons. Ben Wallace = #22 RS, #8 PS
2002-03 - Spurs. Tim Duncan = #3 RS, #2 PS
2001-02 - Lakers. Shaq = #3 RS (Kobe #10), Shaq = #4 PS (Kobe #4)
2000-01 - Lakers. Shaq = #1 RS (Kobe #18), Shaq = #1 PS (Kobe #5)
1999-00 - Lakers. Shaq = #1 RS (Kobe #15), Shaq = #1 PS (Kobe #20)
1998-99 - Spurs. Duncan = #4 RS, #2 PS
1997-98 - Bulls. Jordan = #4 RS (Pippen #25), #3 PS (Pippen #14)
The above stats are borrowed from a post by LarBrd33. He was using NBA.Com's efficiency ratings for his rankings.
I'm not sure that the bolded parts of your above statement are true. It appears that top ten is the new top five.