Digging tunnels

Literally a shower thought. Nothing not already obvious to anyone reading business history though. I'm sure VCs already found a catchy word for this. The thought ? "The best way to get a place in the mainstream neighbourhoods is by digging a tunnel under your niche."
Amazon started with books, Facebook college campuses, Sainsbury butter. What did they have in common ? Very competitive markets with already established players.

Why am I wasting your time for such obvious facts? It all becomes interesting when you start applying such thinking forward. What are the current big fish in small ponds? The companies that could start digging tunnels under their niche ?
The likes of Halo Top (low-calories, high protein ice-cream), Lululemon or Shea Moisture (now one of the US's most beloved brand amongst women - been a user & fan for years now!), that are all already giants in their own regards.

Taking this last example, who would have thought that paraben-free, phthalate-free, cruelty-free (definitely "blah, blah, blah" in the ears of boomers) shampoo company could one day reach such popularity ? A pricy product originally focusing on black women with sensitive scalps and ethical concerns.
(a target group from which your friendly blogger couldn't be further removed)

However, thanks to the brand equity they managed to acquire, and the quality of their original product, and notwithstanding a slight change in recipe that brought complaints of lower quality, they now managed to expand to the whole product range to most skincare products conventional "soap" companies usually sell : from beard oil to hair stylers. Conquer on!