There are so many "niche" businesses out there - that will be enough to bring in millions in revenue - simply because there is such a variety in what people want and need. And we'll never hear of them unless our interests happen to coincide with that particular niche.
Case in point - I've just started working for a company that is an upstart small player in the area of document management for construction companies. You'd think document management was a solved problem and there wouldn't be room for specialists in that area - but no, there are several multi-million dollar businesses that do nothing but. And there's still room for small companies like ours to grow into.
Prior to August 2018, there were no trillion dollar companies, now there are at least 5 (MSFT, AMZN, AAPL, Aramco, Google) and more on the way.
This observation seems more likely to be driven by Aramco not being a public company before 2018 than by Aramco not existing before 2018.
Just because it's a little harder to see something doesn't mean it isn't there.
Their marketing and social media presence is as large as they can get it (I know their former Head of Social media and VP Product). Being successful there is a first step to becoming an influencer. As a second-hand market, they’ve been carried by the environmental trend lately, deservingly so. Their audience is younger, more female and fashion-forward and in that very seeked-after demographic, they have incredible numbers. There are American companies, like Vestiaire Collective, that offer a similar service but Depop is making strides around the world.
There might not be a lot of overlap with your interest, or those of many people in Hacker News — and that’s fine. But, to fin equivalents, saying that TikTok or Tampax are "under the radar" brands says more about your curiosity than it says about a product used by half of the population.
How on earth does Tik Tok or Tampax relate with Depop?
P.S. As a general rule of thumb we try to avoid personal remarks in here when replying to a person. Just to keep the place a bit more civilized.