It was marketing bullshit that many idiots fell for, there was no chance of any real flipping to happen. Are apples going to flip gold one day? They are not even the same things. Most altcoins including Ethereum are very centralized and run in a controlled way. They are the reinvention of centralized finance with new technology. Bitcoin is something entirely different and in its separate class.
Just imagine the amount of ETH that was freely premined that went into bribing governments and officials for support, and still it can't even get anywhere close to Bitcoin. That says a lot about it.