Corporations aren’t allowed to “finance” “political campaigns.” When OpenSecrets says stuff like “Google” contributed $X million to Democrats, it’s lying. What really happens is Google employees contributed that money.
So, yes, I do believe companies finance political campaigns. Whether the money flows through campaign organizations is not an important distinction to me.
Leaving that aside, SuperPACs account for just 15% of election spending in 2016. It’s inaccurate to even suggest that corporate money and money from wealthy donors is the dominant factor in campaigns.
[1] https://en.wikipedia.org/wiki/Political_action_committee
I think it's more than fair to attribute the Google PAC to Google, and not to a diffuse group of Google employees.