Could be, De, but I always fall back on the sure knowledge that conspiracies are notoriously hard to keep under wraps. However, the shooting in Dealey Plaza is certainly one that has been able to maintain its murkiness for 60 years, now. For me, the truth is far more often to be a confluence of chance, ineptitude, and conspiracy.
Is there a Deep State that hates Donald Trump (as well as any Conservative voice that speaks to the dire need to decimate the bloated federal government) and wishes him harm? OH. HELL. YES. But, if anyone conspired with Thomas Matthew Crooks, it would have to be a TIGHTLY controlled operation - VERY limited in scope - because Crooks was an absolute FLAKE. Yes ... such a conspiracy ... at least where Crooks' handlers would be concerned ... would end with the death of Crooks. THAT would be an absolute necessity, but you would be hard pressed to totally control a nutjob like Crooks and prevent him from doing or saying something truly stupid and leave some incriminating evidence. That would be kinda like these moronic teachers who have sex with their teenage students - it's gonna come out, sure as the sun rises in the east. They'd have to keep it extremely small and hermetically sealed to have any chance of getting away with it.
Did Crooks have assistance? Yeah, probably ... but I seriously doubt it involved a cabal of highly placed people and across government agencies. Heck, Crooks might have even received assistance from murky operatives associated with the ChiComs, the Iranians, the Mexican drug cartels, Putin, etc. They could have armed him, wound him up, pointed him in the right direction, and walked away into the mist never to be heard from again.
Again, I find it more likely that it was a combination of chance, possibly some conspiratorial assistance to Crooks, and a whole lot of incompetence on the part of the Secret Service, DHS & FBI born of and exacerbated by inherent hatred of and disregard for Trump. Federal government agencies despise Trump and do not want him to return to The White House, so they're going to flippantly cut corners when it comes to his security.