As I understand it there's actually a whole field of marketing research based on that question. Companies want to know how much a customer will spend on a widget, a nice widget, a really nice widget, and widget accessories.
For example, did you ever notice that reloading components and gear cost between about $20 and $35? 1000 primers, a die set, 100 bullets, 50 pieces of rifle brass, 100 pieces of pistol brass, a pound of powder etc. etc. Somebody sat down and figured out that $20-$35 is about what joe average is willing to plop down every time he heads to the store. Less than that isn't worth his trouble, and more than that and he has to think a little harder before the wallet comes out.
Same deal for guns, seems like $300-400 is about where most people can scrounge and/or take a credit card hit. Double that and you get a "special purchase" gun. Double it again and you have the status symbol guns.
Pistols: $400 for entry level (Rock Island, Taurus) $800 for nicer (Colt Govt model, nice Springfield), $1600 and up for the nice shiny stuff with the big name on it.
Rifles: $300-400 for entry level (Mossberg), $800 for nicer (Winchester Model 70 featherweight), $1600 and up for the really nice stuff.
Manufacturers pick a price point based on their market research and build a gun to hit it. Your question is basically "what's the bottom price point in the market right now?" and it's about $300-400. Nobody will field a gun for less because the profit isn't there, and every bulletin board will light up with "what a cheap piece of junk that thing is." For the same reason, nobody will make one just a little bit nicer because Joe Shmo looks at the $400 Brownberg and the $500 Remchester and doesn't really see the point in the extra $100. If he had that kind of money to burn, he would jump up to the next level and be looking at the $800 rifles. It's kindof a simplistic way of describing it but it happens in all sorts of fields.
Cars are the same, the entry level is around $12000, Mid range runs $24k -30k, and the good stuff starts in the $50s. Each step is about twice the price of the lower one.
By the way, Buds Gun Shop has Mossberg .308win bolt actions for sale right now for $326. Guarenteed to go bang and hit a deer within 200 yards every time...just as dead as with the $4000+ Sako TRG.
-J.