I've hunted my daughters yard several times. The house was built in the 40's. I never found silver in that yard. My parents last house was built in 1958, no silver either. No one ever hunted any of these 2 yards. The best I did in the yards was wheat pennies and they were usually around the driveway and clothesline areas. My house was built in 1970 and I quarantee no silver.
You can go to the bank today and find wheaties in penny rolls today with no trouble, so we still find them. The same goes for older nickels. People don't look at change. I've found many many 1965 quarters because they are still in peoples pockets today. I've found only 3 half's in 2 years. Can you remember the last time you got a half in change? As I remember there is no slot in cash drawers for them.
At least V nickels, buffalo's and Merc's look different and some people might check Rosie's or quarters for silver. I think many wheat's and older nickels have been more resently lost than we think. Rob