Your assumption seems to be that the side that spends more money wins - the prop 16 vote, with the YES side spending 20 million and the NO side spending just 1.5 million would seem to refute that idea.

https://ballotpedia.org/California_Proposition_16,_Repeal_Pr...

Is it possible that maybe the voters actually have their own opinions regarding these ballot propositions? So maybe Californian voters think that drivers should have the right to decide for themselves whether to work with Uber or not?