It's not the same thing. At all.
Pocket is used by people and is a feature Mozilla want to prominently integrate with Firefox. This is due to the financial gains they directly get when someone signs up for Pocket premium.
It's not an unused, dusty feature that's adding a burden to the platform and is a net time + money sink. It's something that makes them money.
As I said, in the comment you just replied to, even if nobody did use pocket then this would be a burden they are willing to take. So, comparing RSS feeds to pocket on the fact that it can be implemented as an extension alone is a nonsensical point.