Even the stupidest player could become a physical 4th liner. Jake could follow kassian's arc (not being a fighter as he sucks at it but being physical). He needed direction from the coach and the team but it seems he never got any. Ultimately its on him to have wasted his physical tools but it's on the team not having taken out of him at least something.
i think the difference is, kassian got his own way a lot of the time but in general he's a decently smart player. he sees the ice well, knows where he needs to be, but was prone to lapses.
jake's lapses are a whole other kind of lapse, because he has to be fully dialed in just to get around the ice and do his job at a reasonable level. if his concentration slips at all, he's a liability.
i would compare him to sandlak. we got tantalized by the flashes and kept him around for way too long hoping he'd flip the switch inside his non-existent brain, then when he was finally traded away he played 73 more NHL games over three seasons before the league was done with him (and those last 33 games were with us, after a hartford team in the middle of a six season playoff drought didn't to retain him and we got him back for free).
i don't see him getting too many more chances after we finally let him go. when a guy has neither the on-ice instincts nor the work ethic, i don't think many teams will give him much more than the kind of shot where he'll have to outwork five other guys which, i mean come on it's jake.