Support local sport with what you can, time, money, your presence.
A lot is chicken and egg problem, no sponsors -> no money -> slow development.
Supporting local sport will help increase revenue -> increase sponsorship -> may speed up development.
Fan support is important because you can't expect corporates to sponsor teams like "charity", without getting something back, because they want advertising, mileage, etc. Imagine from business perspective, why would I want to pay $$$ to have my brandname on the jersey, and advertising billboards in stadiums, when only a handful of people watch a game. Your support helps teams in more way than just the few dollar ticket you pay. You are important.
Do your bit to support, whatever way you can.
My personal view is that a lot of the problem lies in our sense of belonging or relation to a team. We feel we belong to Singapore, and therefore want Malaysia Cup days, where we play outsiders, but not Tampines or Geylang, playing against Woodlands. Why?
In England, I know of people supporting their team for 20 30 years, because it is their TEAM!! Even when the team relegate to 2nd or 3rd division, they are still there. Why?
I think as citizens, we have to also look at what we can do to help bring the spirit back, instead of waiting for someone "do it" for us.