Lore wise Jedi, Sith, and other force users or, more specifically, lightsaber wielders' ability to survive against opponents with ranged weaponry comes from their ability to deflect blaster bolts.
Why don't people interested in killing Jedi rely on old fashioned projectile weapons and flamethrowers? Sure, pre-cognitive reflexes will let you block a blaster, but if you try to block a regular lead bullet you'd only have a super-heated lead bullet slamming into you after it passes through the restrained plasma blade of the lightsaber. Same goes with flamethrowers. Can't exactly block a 25ft jet of burning prometheum.
Jedi and Sith are a big enough threat to both the empire and the republic that it seems like both would invest in equipping units with AK-47s instead of Blastech D-25s if they knew they were going to be facing Jedi.