This is false, the snowden releases showed they have extensive infrastructure that aggregates data from many different sources.
At the end of the day, worldwide profit scales systems faster than even national security dollars.
Granted, they do not snoop on you to the maximum extent the hardware of these devices allow. But, take a look at [0]. Unless you are one of the few people who goes out of their way to limit tracking, do you think that the NSA would be able to get that detailed tracking of everyone's movements.
And this is just the obvious part (which Google is nice enough to share with its users as a feature). Big tech companies have also built detailed models of most people's interests; which is simply not possible without the large amount of data that comes from people actually interacting with them.
All of the NSA's dragnet surveillance is built on the back of private industry, and works because that private industry has convinced people to participate in it.