People are just impatient.
When its the platform holder advertising games it serves a double purpose, to sell the system and sell the software so more extensive and greater marketing efforts are immediately justified. For the third parties their marketing dollars don't serve this double purpose so they must be more scarce with them. As the Wii platform increases in sales and the third parties become more sure about reaching a far greater audience with their marketing dollars they will be more willing to part with them, because as the Wii install base increases the cost/benifit ratio of third party advertising improves markedly. Therefore it does follow that with vastly increasing userbases third parties will find far greater luck selling their games and the incentive for Publishers is to time their marketable releases for when their marketing dollars are most effective.
That is my simplest explanation of why there has been a "so-called" third party problem on the Wii.
P.S To reach a wider/varied audience it is more expensive and effective to use TV advertisement which is expensive in both implementation and design. They can't easily throw a bunch of advertisements all over IGN and expect to reach their audience can they?
Tease.
