Great question — answering as the UphillTech team:
In most cases: No. They don't care about the fans, and care about profits. Most streaming sites have licenses to stream that show, which often enough is for exclusivity, such as with Netflix, or Amazon Prime. The licenses for these shows are either expensive from competition for it, or not worth the cost because of lack of response for the series. In the former case, the streaming site you're petitioning can do nothing about it, considering some other place will most likely already have the license, and in the latter case, can't see enough profits coming from it to make it worth the cost.
Full answer by jFields99: https://anime.stackexchange.com/a/40276 (CC BY-SA 3.0).
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