Presumably it's impractical now
Pushing that hard was presumably somewhat akin to F1 cars... fuel consumption very high per mile/passenger? These days, environmental issues mean new planes have to focus on fuel efficiency (whether legally, financially or for PR I don't know).
Does modern tech mean a plane could go that fast without drinking fuel or is a fundamental restriction of physics that supersonic flight is fundamentally expensive?
And of course the internet means some of the "I need to be in NY for a meeting" cases are removed.