Steem and Hive have the same size user base. If anything Steem has the advantage of a working on-boarding system (I don't think Hive has one yet), is better known, has more existing apps, and has far better SEO. If anything Steem should be better off in terms of network size, unless there is something about Hive that makes it superior, and if there is, that certainly wasn't something contributed (in fact the opposite) by the people who didn't get an airdrop.