I still don't see how there is value to owning <STEEM or why I would want to buy any.

but being able to earn more STEEM is not a reason to buy STEEM in itself.

Why not, though? Let's say it's 2016 again, there are no bidbots, and the only way to earn STEEM is through upvotes on steemit.com. Let's say there's a culture on the site where users who buy and power up are rewarded. Why wouldn't this culture encourage buying?