The failures of security in this case would not have been an isolated occurrence. There is a very high likelihood that this has happened before but without someone testing it like the shooter did in this case.
In most cases, it's the appearance of formidable security apparatus that dissuades somebody from trying their luck. That facade has been shattered. That's never good news.
Erik Prince on speed dial would be my resort
I trust him and his 20,000 man army more than any of the alphabet agencies when it comes to Trump and safeguarding his life plus his guys work protecting folks who are shot at or bombed regularly