Most states just outsource licensing to a professional organization and transfers are a simple matter of filing a form and paying a fee.
If practicing across state lines is lucrative there's not much stopping existing listened professionals from doing it.
the professional org handles certification exam and varying amounts of paperwork verification depending on state but every state has a licensing board to make the final determination and handle grievances
Further, transfers are not always as simple as you describe. Sometimes they are. It depends on the states
The end result of that is that media orgs are now far more cautious about posting “exposes” of powerful people. Gonzo journalism in America is basically dead except for a handful of independent outlets that have much less impact, funding, and reach. Now it’s substacks of people that used to work for the intercept and rolling stone because media with money is playing it safe posting articles about trumps latest antics and 12 vacation spots you have to check out before you die.