The problem is not getting your first 1k users (anyone with enough time and money can do that). The real challenge is how to make a sticky product that people care enough about to tell their friends.
If you've created multiple "things" and it's never been a problem to get your first 1K users/viewers/listeners, you're been amazingly lucky. Congratulations.
You start by pretending you're 10 users to create social proof, then a massive spamming campaign should get you to 100 users, and then you fudge the books and say you have 1k to anyone who asks.
That's generally what the companies listed in the article did too.
