You're right that the question alone might be misleading. I mean every company using your open source package in their development not only FANG etc. The local pizza shop might be using OSS but probably does not have a dev team of their own (they either use a SaaS or have freelancers for their website).
This is extremely poorly phrased. Are you talking about Microsoft/ Amazon/ Google/ Facebook? Your local pizza shop? A percentage of all corporate revenue? Is this "should" as in "would ideally", or should as in "we should shame them if they don't"? I don't think this question is going to get a meaningful answer.