I switched to Google Voice a decade ago, and it took me years to realize the degree to which everyone else was getting spammed with robocalls. I probably get o

I switched to Google Voice a decade ago, and it took me years to realize the degree to which everyone else was getting spammed with robocalls. I probably get one a month. I know they don't have Google's technical chops, but I wonder why carriers don't do this? Unless it's not down to spam filtering, and it's simply that it costs more for automated systems to interface with Google Voice (once in a blue moon, entering my GV number into an automated system gets rejected).