I don't understand why bodies of water are not checked more often when these people go missing?

"Another car recovered from a body of water…
Technology can be a wonderful thing, especially when it helps to solve mysteries which have been plaguing families for years on end. That’s exactly what happened a year ago when a 13-year-old boy used a GoPro camera to take a peek at what he thought was a car deep below the surface of a frigid mountain lake in British Columbia. Little did he know he’d be instrumental in solving a 27-year-old mystery.
Deep in the murky water, barely visible even in the GoPro video was the underside of a car, a Honda from the 1980s to be precise. It had been sitting there undiscovered since 1992. The boy and his parents called the police, who sent a dive team down to check out the car a few days later. To their shock, there was a body inside.
After pulling the car from the lake, they were able to determine a 69-year-old woman named Janet Farris was in the driver’s seat. The mother of two and grandmother of five disappeared as she was driving to her niece’s wedding in Innisfail from Vancouver Island. Her vanishing haunted the family that entire time as they searched endlessly for their loved one"

https://www.msn.com/en-us/news..../crime/teen-with-gop