For steemit: Getting a lot of different phone numbers (which you actually own).
For the steem blockchain: It's not worth it to create hundreds or thousands of bots because it makes no sense. You need to actively vote for good content and as a starter, it's just not possible to have such an effect on your own posts (which could be one reason for bots voting).
RE: More than 700,000 Steemit accounts / Mehr als 700.000 Steemit-Konten