Because safari will sooner or later become another Edge. Apple doesn't invest enough into safari and now it's a browser which is most behind in terms of technologies.
I've seen what happens to web browsers that trail behind the industry in features.
It doesn't matter how nice the privacy features are, when a user encounters web site after web site that doesn't work right in their browser, they eventually each out to a more technical friend that recommends trying browser X. When browser X fixes their problems, they never return.