Umm, no - this is not just a 'common trope'. The CTO of Vizio has stated in multiple interviews that removing the data collection capabilities of their TVs would increase the prices. Direct quote:
"The greater strategy is I really don't need to make money off of the TV. I need to cover my cost."
and
"It's not just about data collection. It's about post-purchase monetization of the TV."
Right, but the value of the data pulled from a single TV is probably around $10/yr (how could it be higher?). Over 10 years that’s $100 - sure - but do people keep Vizio TVs around that long?