Am not a numbers guy. But what I do see is that NSP had a chance to take down Tampines in the same way the WP took down Aljunied, but they did not do so.
Subjectively, I feel that Aljunied, compared to Tampines, has been helmed by more capable ministers with better PR and ground support. Why then did WP succeed where NSP failed?
(a) Unlike WP, NSP did not build itself in the grassroots in the '90s up till 2006. LTK used the long years to establish himself firmly. This is quiet work, not reported by the press, so the internet heroes cannot see this. When 2011 was ripe, he had the chance to move out and claim an GRC victory.
(b) The opposition fell as a whole in the 1990s. That much is clear. In 2001, WP was no different from the rest -- weak, performed poorly at the polls, etc. So why did WP move ahead of the pack? I think its because while the others were mired in internal squabbles, WP took the time to quietly hone its political instincts and stay out of the "fray". The distance put between WP and the rest, which some mistake as arrogance or isolationist, worked to its advantage. When others are strangling each other, do not offer yourself as rope.
(c) WP developed better branding even compared to other parties who used the internet more aggressively. This shows that grassroots work is more impt than internet engagement.