The transporter is also established right from the start as being capable of moving intricate pieces of machinery that would cease to function or start to malfunction after fairly minimal faults in the process - say, human beings. Crude magnetic fields (or forcefields) are probably a breeze in comparison.
As for the issue of long distance beaming, it would seem the cooperation of Scotty and future Spock resulted in reproduction of the technology of the masters of Gary Seven. That one was a conventional transporter (since our heroes were able to intercept the beam with their systems) but with extremely long reach, both in terms of endurance and targeting. No doubt Starfleet considered sensor readings on that beam the greatest intelligence payback from the mission to 1968... But reverse-engineering even bits or pieces of the technology might have taken them, or the Vulcan Science Academy, five quarters of a century. Competing star empires are probably far behind. So the question becomes, does "Scotty's" technology remain open to inspection, or did future Spock make a black box out of it, so that Starfleet will again have to struggle until the 2380s to make heads or tails of it?