/jp/ - Otaku Culture

I'm having trouble understanding the grammar of this sentence
From I've seen the structure V (masu form without ます + もしない is supposed to expressed dissatisfaction but in this case with the potential form, does it express inability?
And 気 after a verb denotes intention right? So うまく話せる気 is like a noun, can you still put もしない at the end anyway?
Finally does し at the end indicates that's a reason or am I mistaken?