The Grizzlies had great attendence when they were a 50 win team. The Kings were considered the load house of the NBA when they were a WCF team. It's all about winning ball games.
While I agree that winning is the biggest key to putting butts in seats, the year Memphis won 50 games, they averaged 15,188 home game attendance - 25th out of 29 teams.
The year after their 50-win season, was their best, in terms of attendance, in Memphis at 16,862 per game - 19th out of 30 teams. They won 45 games that season.
The year after that, they won 49 games and averaged 15,793 home attendance - 27th out of 30.
So, they made the play-offs three years in a row and only topped 16,000 average attendance once - and only once made it out of the bottom 5 in average home attendance.
So, even when they were winning, they weren't exactly packing them in (~85% of capacity over those three years).
By comparison, last season the Blazers won 41 games and missed the play-offs. Their average home attendance was 19,550 - 7th in the league and about 98% of capacity.
This year, they are on pace to win 50 games, should make the play-offs, have sold out every home game, and are currently 3rd in the league in average home attendance at 20,497 - 102.6% of capacity.
That's the difference between Portland and Memphis. The Blazers have sold out every home game since late December 2007 and it's not going to get any easier to get tickets now that they are on the verge of making the play-offs. In Memphis, even when they were making the play-offs three years in a row, 15% of the tickets went unsold.
BNM