Yes and even besides traditional methods like user research, there are lots of indirect ways to measure the success of a product without resorting to invasive d

Yes and even besides traditional methods like user research, there are lots of indirect ways to measure the success of a product without resorting to invasive data collection practices. For instance, you can track downloads, page views in documentation, the number of times a certain endpoint is pinged on the server etc. while still respecting the privacy of the user. The practice to track a user's behavior across a wide array of products imo crosses a line, and is not needed to inform good product development. A company could probably sell better to you if they hired a PI to follow your movements, and tapped your phone line, but that doesn't give them the right to do so.