Well during those 20 years, they were one of the best teams in the NBA.
they signed Artest as well before the 2010 title.
Nash was definitely a player of consequence. He shot 53%, which was a career high, from the field and made the All Star game. His back was fried which the Lakers blew, but at the time that was a huge signing.
The Lakers were just the top of the league and maxed out most of these last 20 years. The last 3 years, they have had shoddy management which has lead to no one wanting to play there.