I think the simplest way to measure that is by asking 'what would we truly lose if this company disappeared tomorrow?'. With one follow-up question of 'how easily could the important bits actually be replaced?'
I think it does the opposite, it makes you think about whether the company is big because of its products/services or other reasons. It's not a yes/no answer, it's a prompt.
> 'what would we truly lose if this company disappeared tomorrow?'
I guess such a big company is here because they managed to create a need. The question may be: "were we really worse off before we had what this company built?".
Example: if GitHub disappears tomorrow, that's likely a pretty big problem. But we were fine before GitHub, we just had different (not worse) workflows. GitHub created a dependency.
It's much more helpful to ask, "What would we lose if this company were broken up tomorrow into parts no larger than (say) the median company size?"