I wonder if the case isn’t that we don’t allow new technologies to be truly decentralized. Email and web came from a time before... our market/startup forces in play today may not yield a new, true decentralization because the urge to monetize is stronger now than before.
Technically it can. You just have to use alternate old school advertising practices to get discovered. Radio/television spots, word-of-mouth, Billboard, etc...
The very fact you think it is impossible to reach end users without using Google should highlight just how much they have cornered the market.
Remember, internet search was not always a given, and the worked just fine.