For the same reason that one million liberals didn’t leave the USA when Trump was elected. It’s just a bunch of lame gas. It is so easy to tell a pollster one thing and never actually follow up and do what you said you’d do.
They didn’t leave the area either as they promised when Ronald Reagan, George W. Bush and Donald Trump were elected. In other word: Promise, promises and as the saying goes: Promises are cheap.
One word
Rawanda