I don't think you can rule out foul play.It was a big blunder on this case because so much time was lost the beginning by missing that cctv footage of Jack crossing the bridge. Placing him in a completely different area. Police were searching on the wrong side of the river. But what are other people's opinions on this case, does anyone suspect foul play?
My theory is the same as it was in the beginning; when someone goes missing near water, they're normally in the water. I just think it's such a dangerous location to be walking alone drunk, there is so many spots you can end up in the water and because it's so tidal it removes the evidence quickly.
I spend a lot of time in Bristol and like it a lot but that's not a location I would feel at all happy to find myself in late at night (with a broken down car for instance). The combination of the water and the mishmash of roads makes it a kind of liminal zone where pretty much anything could happen. There's a lot of wasteground and dodgy little hidey holes. I do think the police have dropped the ball. The combination of cctv and his phone's last known location gives a clear steer on the area to focus on, and they could have been out doing door to door and collecting cctv and doorbell footage, plus an appeal to drivers for dashcam footage. It would have taken ages to go through it all but by now it might have been offering up some new leads.
The other strong possibility imo is a hit and run where the driver disposed of his body.
An accidental death involving water can't be ruled out because it's so often what's happened with young men on a night out, but without a body should only be a conclusion of last resort, whereas it seems to have been a go to demi conclusion in poor Jack's case, which is wrong. I might feel differently if there was evidence of stress, depression, a relationship break up or whatever, and a suspicion he'd gone towards the water to brood and might have been suicidal. But afaik there's been nothing of that sort said or in his history. And I don't believe in a waterside homicidal 'pusher' for a minute. I'm sure there was a strong belief in one in Manchester a few years ago, after a spate of drunk young men ended up in the canal, until one of them was caught on cctv and it was clear he was just incapacitated, no one else involved. People want death not to seem stupid and needless, and grasp at explanations that allow it to be someone else's fault imho.
But Jack's case could be something else and needs to be investigated more thoroughly imo. It might not be too late to find some more footage of him.