It’s not that police can’t use tools that arent available to the general public. It’s that in the US we have the plain view doctrine which defines the boundary between the things that can be plainly observed in public, which don’t constitute a search and thus don’t trigger the 4a protections, and observations that are not plain view observations and which are a search and trigger 4a protections

OP's contention is that private citizens don't have access to a network of cameras to look for license plates and therefore it isn't "plain view", but I don't see how that's different than law enforcement being able to muster the entire nation's cops to look for a suspect.