And every man and his dog seemed to have the resources to do so in the Star Wars galaxy. (I mean hell, apparently in one of the novels the HUTTS built their own weird death-star thing.)
You must be talking about the Darksaber. It was indeed a project commissioned by the Hutts, and was pretty much a shoddy Chinese knockoff of the Death Star's main armament strapped to a rather unstable powersource. In no way did it have the defensive or tactical capabilities of either Death Star, or even a moderately-sized battlestation. To be frank, it was a piece of ****.
While superweapons seem to be a dime a dozen in the GFFA, they're generally confined to pan-galactic superpowers, rather than comparatively tiny crime syndicates.
I don't recall railguns being in Starwars
Mass drivers do exist in the Star Wars universe. While not exactly standard Imperial weaponry, the EU has shown a large number of railgun-type weapons at all scales. Ranging from the fragile, handheld Verpine Shatter Gun, to the mass driver cannons seen on Vengeance-class Frigates. The EU has an answer for everything. So it's not hard to imagine there would be scaled-up fixed orbit defenses with mass drivers, although I'd wager a Golan-class platform would be far more effective, given it's rather varied supply of armaments.
In fact, lasers probably explain why there aren't that many mass drivers in the Star Wars universe. For a society that seems to have discovered dozens of ways to generate cheap and plentiful energy, it is thus far more efficient to build a giant ****-off reactor and channel it into a giant ****-off energy cannon. That way, you don't have to worry about ammunition, nor recoil. Plus, if memory serves; the output of a single turbolaser turret reaches well into the
gigatons of TNT equivalent. Why bother with a MAC platform when, as previously stated, you can just get yourself a Golan-style setup with a few dozen turbolasers
to start with. Plus, considering the technology exists for
planetary shields, singular platforms are hardly the only way to defend your world.
Relating to the original question, though: Yes, general technological level throughout the GFFA seems to be at a scale that would allow for any number of fantastical defensive options. Ignoring the requirement of a very solid industrial base as well as the technical expertise to build such a defensive array, I'm sure most planets would be able to throw up dozens of railgun platforms. Hell, they probably wouldn't even break a sweat.
However, the fact remains that the person on the defensive is always at a disadvantage. This is magnified when trying to defend a target as big and as stationary as a planet. It would take an ungodly amount of platforms to make any serious defense against even a small fleet of mobile starships controlling everything past a high orbit. When you introduce ordinance like missiles that could dodge incoming fire, or the presence of fighters that could manually swoop in and annihilate any orbital infrastructure, there's not much a planet can do.
Plus, if a planet is giving you too much trouble, just blast the **** out of it. Or drop a few asteroids on it. A railgun platform isn't going to do squat to a rock the size of a small country hurtling towards a planet. Just keep annihilating parts of the planet until it either surrenders or there's nothing left to conquer. Hell, the threat of such action should be enough to prevent any world from rebelling. So sayeth the Tarkin Doctrine.
On a side note; I saw this rather interesting experimental art piece yesterday. Specifically, it was the left third of
Star Wars, the middle third of
Empire Strikes Back, and the right third of
Return of the Jedi, on the same screen
at the same time. Essentially, all three movies together, at once, in a 2 hour sitting, with the sound mix varying and overlapping between them. Quite the experience.
