This always strikes a cord with me...
Having been inside of hundreds , if not more than a thousand , different airguns... and seen firsthand some of the inner workings of AAA, Daystate-BRK, Thomas and FX, I very much understand they are trying to bring us a product that will sell.
You can absolutely, no question, buy your perfect barrel and most likely any other components ... just bring money... LOTS of money... Back when Woody managed LW-USA, I had that very discussion with him about barrels. LW can and will make you a perfect barrel if you're willing to pay for it. Lillja can and will make them to your spec as well. If you're willing to work for it, TJ can give you a less expensive one that can possibly be really good... they just take a LOT of work to finish.
Most ALL products we use are tradeoffs... airguns are no different. There are decreasing returns for very rapidly increasing costs and effort so perfection is more a combination of getting good enough performance at an sellable price.
For a couple of opposing views, Mike of Thomas rifle fame delivers a pretty finely designed and built competition rifle that I generally think of as expensive, but ready for competition. With the work involved in assembly , tuning, and testing, his hourly wage is quite low. Why does he do it? Love of airguns and competition , I would guess... Tom at AAA is similar but on the hunting end of airguns, not so much competition. At the other end is Crosman. We could buy parts direct from them at one time and I bought a spare barrel for my 140. It was $9 and this was not a closeout or special deal. How in the world could they make a fitted, rifled, and blued steel barrel and sell it for $9? They had just refined the process and designed out every bit of wasted cost with the plan of making a LOT of them. You can see that in every product they sell. I read a statement at some point that they felt they could be more successful selling 1 million for a $1 profit than 1000 for a $1000 dollar profit.
Anyway ... I tend to look at things in their value to me but can easily see the surface costs of the product manufacturing... it's either worth it to me or not but I am not a person who expects to get something for nothing...
Ammo is similar ... apparently there's a good number of people not old enough to remember what ammo was like at one time. Shooting 100 yards with a wadcutter ...

Fifty yards with a 6 ft lb springer and wadcutters



JSB has kind of revolutionized pellets with their higher bc domed offerings, much like Crosman did with the Premiers in the late 90's. Others are following now...
I feel we are in kind of a Golden Age ... carbon fiber tanks that weigh so little and hold so much, affordable compressors, ammo, accessories ... it's all so GOOD...

I think that valving still has some room for gains like the hammerless and balanced valves , for instance. Not so sure about anything else on the rifles as it's all cosmetics or ergonomics from my perspective. Probably some combinations of features in there, also...
Just my $0.02...
Bob