I guess it depends on how we define culture. Certainly every community, be they a discord server or a twitch chat, has its own micro culture. Memes, references, trends, acronyms or phrases, and symbolism come to mind. I don't doubt that Bezos's power over Amazon over twitch could get some emoji they like banned. But I don't think that's as active a control a culture as I think the article implies. Bezos isn't personally producing a twitch stream the way Broadway producers would. Sundar Pichai doesn't mandate that the casting for a YouTube video isn't what he wants. To say they control culture feels disingenuous to the creators.
Arguably you could say that in the days of the monarchy we only had 1 person, the king, controlling our culture. And I'm sure there's influence. But at least personally I've never heard anyone hold that viewpoint.