In general, that's true. But Firefox is an exception to this.
The most important thing to a regular user, is that their websites work. But for websites to work, the developer had to test in Firefox. So, Firefox's alienation of power users has hurt its regular userbase.
There's also the distinction between users vs customers. Most users pay nothing for Firefox. A relatively small number of free-software lovers provide donations. If they want more of those people to give more money, Mozilla would have to cater to power users. This leaves Mozilla's main customer as being Google, who doesn't really want Firefox to be good.
The other exception to this, is if the software you're making is so specialized, that you can get by on a handful of large institutional customers. Obviously this is not where Mozilla is, it's just another case where telemetry is not necessary.