It would hardly matter because such users are probably still, and always were, an absolute minority of Firefox users and, more importantly, data-driven design often assumes equality of users unless somebody has gone out of their way to justify violating that assumption. And the easiest/most common way to violate the assumption of user equality is to point at other data, such as "only 1% use that feature but 50% of those that do are whales who account for 90% of our income."

But when the matter is less concrete because the value of one particular minority demographic is hard to pin down in the collected data (from what in the mozilla's telemetry data can you persuasively derive the value of power users who tell their friends and family to use firefox? Uncovering those relationships would certainly violate users' privacy..) then "data driven" decision processes will by default assume all users have equal worth.

Another big example is Linux. If you ever wonder why developers don't bother to support your Linux distro, try turning on telemetry once in a while. It'll help.

There are addons for RSS support that are much higher quality than the built-in support.

The removal of RSS is just an example of poor management and decision making by Mozilla.

I think that even if telemetry had had different results, they would have then just ignored it for making that decision. Or they would have changed the interface to hide a feature, and then when users used it less, they would use that as justification to remove something.

There was really no good reason to remove it. They quantified the costs of keeping it at something like $5000. How much do they spend translating Firefox into obscure languages that nobody downloads? Or on catering for their galas and fundraisers? Or any other stuff not related to writing software?

There is much more robust discussion on this already. https://news.ycombinator.com/item?id=18202028