I think there will always be an element of those at the top and those at the bottom. Those who came into Hive early are likely to have earned more and have more clout on the platform. They are also the ones who are more likely to be able to regularly cash out some of their Hive. But, as long as Hive remains a viable crypto currency, there should be enough room for many more to make money from it. For me, the crypto side of it is just an added bonus. Although I would like to earn enough Hive to make my efforts worthwhile.
While seniority on the platform definitely leads to more social clout (and more rewards from the reward pool), any newbie can have more voting power than a low investment old-head. All it requires is to have more capital. Jeff Bezos could come in right now and become one of the largest holders of Hive if he wanted. And with that we'd all become a lot richer (obviously), but our voting power remains the same. Bezos would gain dramatic powers to influence the direction in which the blockchain grows, and there would be people who court him to try and get large upvotes from him.
That's an interesting point. I suppose that someone with a lot of capital could in theory own a lot of the blockchain. Although I'm saying that as someone who doesn't really understand how this thing works!