Well, what an odyssey of a thread that was! Definitely worth reading. Ol' Jack's a fascinating creature, and no mistake, no least for how much of an inkblot test they - if there even truly was a single serial killer - continue to be. They almost literally could have been anyone.
When I started this thread, I selected "None of the suspects yet put forward" in the poll, and still think that most likely. If there really was a sole, tangible Jack the Ripper, then they were a nobody, just another face in the busy, many-textured milieu of the East End. Someone who lived, worked and - at least on the surface - seemed to belong there. Just to speculate a while, it was mentioned at some point that butchery was a common line of work in the Whitechapel area - given the Ripper's proclivities, surely it makes sense that he was a slaughterman?
That way he - for simplicity and likelihood's sake we'll say he, and for sake of argument we'll call them Jack - could have satiated his dark desires through his job. They certainly wouldn't have spawned fully formed from nowhere; they'd have grown and been nurtured, even wrestled with, and work that helped deal with them makes sense. Of course, at some point, butchering wouldn't, for want of a better phrase, have cut it any more...
So Jack moves from animals to humans, as many an escalating psychotic has. Why prostitutes? Being mercenary about it, they wouldn't have been in short supply, they'd have been vulnerable, and often solitary, and would be among the least likely to draw the full attention of the police. A suitably Victorian measure of misogyny would have helped his choice, too. Maybe that was exacerbated by having contracted syphilis from a lady of the night? I've little doubt a hatred of women in general and prostitutes in particular was part of Jack's psychological make-up.
None of that's to say his new course would have been easy, mind. He likely took a fair while to build up to actually killing, with many a false start, and many an attempt aborted through loss of nerve. Even when he did finally take a life - Mary Nicholls - fear of interruption, maybe someone starting moving too close by for comfort, prevented him from truly satisfying his needs. Annie Chapman was the first time he truly got to indulge his hungers, and it sated him...for a while.
When they inevitably came back he went hunting again, possibly with a shorter, easier to conceal knife along with his trusted friend, found Liz Stride, but was spooked away before he could get started. Maybe that, and the shorter knife proving inadequate, provoked a great frustration in him, ensuring that when he came upon Catherine Eddowes, he threw caution to the wind and didn't hold back.
Maybe that led to him coming within a whisker of being caught; when her body was found he could have been but a street or two away, where he found some freshly daubed graffiti; in a panicked attempt to confuse matters he dropped the piece of apron he'd taken near it, then continued to flee.
By this stage the Ripper was real and feared, and the East End must have been buzzing about it, fueled by the media (the more things change...) so he lay low, kept to himself, stayed as quiet as he could for more than a month. Then the needs came back, and he knew he needed to go further, but how? Then he hears, in the blizzard of rumours and fears the area must have been swirling with, of a prostitute of near-identical name to one used by his last victim, who has secluded lodgings in Mitre Square...
This time, indoors, where he won't be interrupted, he indulges completely, savours every slice. He even poses her remains for one last rush as he passes the window on leaving. Maybe, by this stage, he's growing confident, starting to believe the luck of the Devil is with him, and wants to taunt people, taunt the police, so makes a show of his work. Jack's a legend, now.
Maybe, for a while, he believes his urges have been so satiated they're gone for good, but they're not. They return, but now, he has no idea what more he can do. He's experienced his ultimate high; where to go from there, especially given the whole city's on high alert? The hungers give no quarter, though, and in the end there's only one person he can take his knife to - himself. No-one notices - what's one more sad little suicide in the East End, not least when the Ripper's still abroad?
Whoops - got carried away. Then again, that seems to happen to a lot of people where Saucy Jack's concerned...