I’m pretty sure they do use lightsabre technology all over the place: What do you think all those forcefields are?
Now, the personal forcefields we’ve seen, while good at blocking stuff, aren’t quite as good as a lightsabre. But that, I think, can be chalked up as a matter of scale: The “solid” part of a lightsabre blade is very thin (much thinner than the visible halo), and a field meters across of the same strength would probably have prohibitive power requirements. You could maybe make a cage of sorts, which might be effective against slashing attacks, but wouldn’t do much against blaster shots (without the Jedi reflexes to block them), or against thrusting attacks. And we’ve also seen that where power is abundant (like in the generator room for the climactic fight in The Phantom Menace), there are large-scale lightsabre-proof forcefields.
I’ve also seen it posited that, while a lightsabre itself is purely technological, the construction of one requires a level of precision not easily attained by the technology of the day, and so practically-speaking they can only be made by Force-sensitives. There’s also speculation that the Death Star’s main weapon isn’t properly a laser at all, but effectively a giant lightsabre blade, which accounts for why they need massive amounts of the same khyber crystals as are used in lightsabre construction.