I still prefer blued steel and quality wood on long guns and metal frames on handguns. Tolerances may be better now, but there's no way anyone can say a Remington 770 is a better made rifle than even a 788 from 40 years ago. Most every company makes different levels of quality from entry/budget to high end and has for years. High end stuff may not have changed much, but the budget lines aren't even in the same class quality wise as budget guns of 40, 60, 80 years ago.
If you think of it in terms of useage and maintenance, we now have so many ways of cleaning and caring for our firearms. For years most of the cheap guns were for the most part tools for putting meat on the table, eradicating pests, or protection. If the owner was proactive, they'd get some 3 in 1 oil occasionally and a patch through the bore. And yet, there are literally thousands of single shot shotguns and .22 rifles from the 30s-50s still available and functioning. With the best care available, what are the chances that Remington 597 or 770 or Ruger American will still be functional in 75 years?