Finding a niche is one thing. If you change a product used by a portion (albeit small) of the mainstream into a product that would appeal only to a niche audience, that may well end up going against you.
The causal arrow points the other way. Today Firefox finally started blocking third party cookies (some, not all as Brave does; they use Disconnect.me's 3rd party cookie blocking list) by default. This does not limit mainstream appeal, it follows Safari and Brave, who have been leading the privacy by default movement among browsers.
