Its not like it NEEDS to be done by KyoAni
But, Gatoh is the author and he mostly works with KyoAni nowadays...
I want* my 2D mechs and the only studios who might (and even that's not a guarantee) are BONES and KyoAni.
*Replace want with need
I'm still fond of FMP, but I don't know why they'd work on the property again - there's no real incentive anymore for kyoani. And I'd hope that Takemoto is working on something not FMP.
I think a new FMP will happen at some point, but it's not going to be anything fans will be happy about.
It definitely wasn't KyoAni's best selling series (rather the opposite I guess). That said the low sales could be possibly compensated for by an Another! sales increase. We've seen a bunch of sequels get greenlit due to manga/novel sales. Also staff interest can do wonders. I want Takemoto to do one big hurrah then he can work on however many Hyouka sequels he wants.
Now Another! anime is probably coming but I doubt KyoAni would do that one.