Maybe it' just my good luck, but I have owned Rugers since back in the 60's and Smith's in the 50's. I have Remingtons, Winchesters, Sako's, Marlins, Glocks, Springfields and others. In over 50 years of shooting, I have never sent any firearm to the factory for repair. Considering the quantity of firearms being manufactured for military and civilian markets, it seems the factories have a pretty good record.
However, there is no excuse for poor service. If you were to send nearly any firearm to a gunsmith for repair, it could easily take months. Not trying to make excuses here, just trying to put things in perspective. The trick is to have enough guns that you don't need or miss the one being repaired or customized.