Why do people still use Nielsen Rating system when its incredibly inaccurate?

[Mr Khan]

thismeintiel said:
What they should do is ask eveyone who owns a cable box and/or sat. dish if they wish to participate in the nielsen ratings. If yes, then they allow them to collect their viewing data and maybe knock a couple bucks off of their bill.

I want to say everyone who has cable or satellite now is basically doing this, since most providers now require a box (no more analogue cable anywhere, so even if it's a very simple box, it's still a box), so they should be able to pool ratings data for cable or satellite networks, and it would only be the broadcast channels where the problems come in, which of course, are still the most important.