As I understand it, Owen K.C. Stephens was involved in the design work for the Star Wars Saga Edition ruleset. One of the design decisions in that system is that attack damage (and AC!) scales by character level, in addition to damage provided by the weapon and any other feats or talents. This design choice, I have heard it argued, is setting-appropriate because Star Wars has never been about min-maxing equipment. Characters in the setting are typically seen going about their business without fussing over min-maxing weaponry or equipment. Han doesn't "upgrade" his blaster pistol over the course of the series. Hell, most of the characters don't even wear armor.
In Pathfinder, as well, a longsword is a longsword (not a "rusty longsword" or an "azimuth longsword") and the gear race involves accruing magical versions of the longsword or other pieces of equipment that let you accomplish things beyond the limits of mundane equipment, ie something other than just straight damage. This is also, arguably, setting appropriate. Magic stuff is powerful. Magic stuff is not easily manufactured. Some of it comes from a distant age of legends and can't even be made anymore. Magic stuff is worth fighting over and spending outrageous sums of money for.
Have there ever been any design or setting reasons advanced for why Starfinder has structured its weapon tiering system the way it is? Why does the highest tier laser pistol do more than 8 times the damage of the first tier pistol? Why are these items so rare that finding them is tied to your character level and not to the settlement level in which you are searching?
What is it about the Starfinder setting that makes this design choice appropriate? Are there other d20 rpg systems that tie weapon damage so tightly to the tier level of the weapon, as opposed to the various feats and traits picked up over levels?
I think I understand the mechanical reasons underpinning the design choice, in the same way I can understand why Mass Effect 1 had me grind through progressive tiers of what was functionally the same weapon in an effort to balance encounters and give me something to spend my otherwise worthless money on. I guess I just feel less inclined to ignore the world-building ramifications of such a design choice in an P&P RPG than in a video game...