1. Few guns, that us every day mortals can afford are put together hand hand fitted like the good old days up through the 1970's for premium branded guns. This means that parts that mesh or work together have to "wear in" and should do so with proper lubricant.
Springs are also a part of this same equation. New springs will initially relax with use when a firearm is new, and then settle in to a very long period of the spring strength remaining fairly constant. Also keep in mind, a spring at rest, either compressed or in it's normal uncompressed state will not lose strength. It is only the exercising of the spring which causes any loss of strength, and this happens very slowly over thousands of cycles.
At a thousand rounds or cycles, all guns begin to start hitting their sweet spot and will continue to do so as more rounds have been fired through them. I haven't shot but 4 1911's besides my own. When mine was realitivly new, it seemed to have a really good trigger and at the range, I was able to fire Smokewagon's PT 1911 with over 2,000 rounds through it at the time and that trigger was like butter and the feel of the gun through just handling was more like a glove.
I seriously believe today's guns improve with age and use. Sure, parts will break and wear out, if you shoot more than the average bear, but that is why they make parts
2. Along with the fact that guns are not hand fitted, they are otherwise made with CNC mill machines (Computer Numerical Code for those of you who always wondered but were afraid to ask), injection molded plastic or MIM metal parts. Two things happen, mill dust doesn't get cleaned out real well and winds up in less than useful places, and mold mark edges are not smoothed down real well and flash can also break off and wind up in less than useful places, so cleaning the internals you can easily get to is not a bad idea.
3. With semi-autos, there is a feed ramp just below the bottom of the barrel. This is a guide for the bullet as it is stripped from the magazine and fed into the chamber. Many manufactures today, do a good job of polishing this feed ramp, many do not. A few will shine like mirrors, some are shiny and others are dull. Most feed ramps are integral with the barrel, some are part barrel and part frame. Shooting a lot of fmj helps smooth up a feed ramp as each bullet cycled will deposit an amount of metal into the micro crevasses in the (usually steel) metal of the feed ramp. I do a fluff and buff on every semi I buy with a Dremel and polishing cone coated with Micro fine or any other good automotive cleaner wax. As a result, even wide mouthed hollow points work pretty good from the get go.
4. As mentioned, any imported firearm will have protecting coating and usually, the protectorent coating will be pretty stiff. Try dipping anything in syrup and then let it harden a few days and see how well it works.
Overall, good cleaning, proper lubricants and use will eventually give the feel of a Swiss watch with most firearms.