This is one of the ideas, gradually lowering it to a certain point, but we'll see.

For the initial investment, you're certainly right, people did buy Hive to buy HBD (since most major exchanges are still adamant on not supporting it due to various legal reasons) so there would potentially be an initial selling spree (HBD > Hive > Sell) but I would not necessarily call that "HBD is keeping Hive alive" in itself.