It doesn't have to. G2 are probably the most marketable org across all esports yet in no sport are they actually top 1. Possible sponsors look at how marketable the players are, how popular the org already is. Team popularity is mostly based on its players, If the entire fnatic team decided to join navi, then fnatic would lose 95% of their fanbase. Same would happen to sentinels, if tenz were to leave for let's say NRG then NRG would get his fanbase. Making a winnable team and giving them salaries takes a lot of resources and effort, just being good enough and hype brings more and with less resources