Don't think we've ever seen Hollywood in the modern era without unions, so not sure how you can claim it's "undeniable" the industry is better off. We basically have no clue if it's better off or not.
Unions are intended for industries where a worker doesn't have a marketplace of options as there is a single or just a few employers (e.g. Hollywood, teachers, coal mining towns, hospital staff, etc.). Unionizing at Google makes no sense, as there are thousands of tech companies hiring engineers in the valley -- engineers can "collectively bargain" with Google by simply leaving and working somewhere "better".
The reality is that Google is an easy place to work relative to how much people get paid. People don't want to leave a cushy job for one where they would have to work harder for their money, so instead, they are trying other means to have their cake and eat it too.