That's pretty unfortunate. I think Pocket was probably one of the best services that Mozilla offered (outside of Pocket). I find it worrisome if Pocket was not a profitable avenue for them.
I used it for a while as my read-it-later but it ended up being too expensive for the usage I made of it.
I'm pretty worried about Mozilla as a whole. I feel that none of the projects I remember in the past 15 years have actually worked out. Pocket, CommonVoice, Servo, Mozilla Location Services.. It's a shame, really.
I hope for them that Relay and VPN still manage to work out though I've never really been interested in either unfortunately.