I like @conder's comment best.
As for this thought:
When I started coin collecting in the 1960's, it was by searching pocket change. My memories are that mostly you saw coins of the previous 10 years,
I also started my US collection in the 1960s, and while I agree that most of what you saw was, say 10 to 20 years old, it was great that you could routinely find two types of nickels (and the occasional V), two types of dimes (and the occasional Barber), two types of quarters (OK, quarters are even better today), and two types of halves. I was filling albums back through the 1920s easily (filling up tubes with Lincolns from the 1930s), and for some types back into the teens. Regular 1909 P cents could be found in circulation at the rate of maybe 1 every year or two. The older dates were not found every day, but going through my dad's pocket change on a routine basis, turned up all kinds of stuff up to 50 years old.
So, indeed, today part of the problem may be that today's 50 year old coins are still the same type (blech).