what do you think the people standing in the street debating society, natural philosophy, and politics were? Or even are, plenty of people influence those around them without ever getting on the internet. They just don't always get paid for it.Then trying being a influencer without the internet.
While you aren't wrong, that the internet is a requirement for an influencer as we see it today. It seems unlikely that any empire in stellaris that could reasonably said to have such an influencer wouldn't also have some variation of the internet availed by default. at least a planet local internet even if it isn't directly connected to the wider empire.