I think their point is that no matter how secure your base password is, once one site leaks it, the bad guy basically knows your password to every site.
I have been using the internet since the 90s, my Hotmail account is 23 years old and I have never lost any of my accounts. I think it’s working quite well in my experience.
or it just continues working for another 23 years. Do you have a password system that has worked successfully for as long? Just because you “feel” that it’s not good doesn’t mean your feelings are correct.