I don't have to
repeat hauls
oh?
Unless it's been changed recently, so far as I know characters can't access customs offices of other characters even if they're inthe same corportion. Has that changed? If not, even if two characters have identical setups on the same planet, you'll still need to warp to each planet on each character to pick up, import and export goods. That means logging in, undocking, warping to each of your planet to import/export as needed, warping back, switching characters then repeating the process.
Also, industrials do not have infinite storage capacity. My own experience with PI has been that even a single character is able to not quite but almost fill an industrial with goods every month. In addition to hauling materials between planets, at some point you need to actually
sell the finished product, which means transporting them out of w-space and to a market. You're not going to be able to fit 36 character weeks worth of goods in an industrial. You probably could if you use a freighter, but weekly trips...that works out to ~3.6 billion worth of goods which would make you an incredibly attractive suicide gank target. You could stagger it so that you haul roughly an account worth of cargo every few days, maybe in a T2 industrial, but that still means 2-3 trips per week.
Finally, have you factored in
wormhole logistics? Wormholes collapse on a daily basis, and more often than that if there's a lot of heavy traffic. Pretty much every time you take goods to market you're going to need to scan down an exit, and it will put you in a more or less random system that might be any number of hops away from a market hub. And that's assuming you're in a class of wormhole that consistently connects to k-space, rather than a class of wormhole that generates exists leading to other wormholes spaces. You might want to check into that, because if you're making regular trips in and out...yeah, I think you're going to want to make sure you're in the right type of wormhole.
Even so, since traffic through a wormhole encourages it to decay, it's sometimes going to happen that after leaving w-space, the wormhole will collapse behind you. This will require you to log on to another character inside the wormhole and scan down an exit again from the inside to your other character, which will again be to a random system, potentially requiring you to make any number of jumps to get to the known space system that has the wormhole that connects back to your wormhole system. and you will need to get that character back, because you'll need him in the wormhole to move goods around, since as mentioned...characters can't access customs office to get to goods being procured by other characters.
If you're going to do this, I highly recommend you be sure understand how wormholes work before you invest any large sums of ISK. On a bad day you might go through your allotted 4 hours/day simply trying to get home and not even succeed because the wormhole closed behind you, then after finishing at Jita and scanning down the new entrance...after travelling halfway cross the galaxy in your painfully slow industrial ship to get there, and after dealing with lowsec gatecamps on the way, by the time you arrive somebody else has collapsed the new entrance requiring you to scan the new one yet again which might again be on the opposite side of the galaxy.
Assuming 5 minutes an account twice per day
If you're
only talking about refreshing extractors, I find that five minutes once a day is enough for that. You might be able to get away doing it less often because resource generation rates are supposed to be much higher outside of highsec, though I can't confirm that personally. Once a day is enough to keep everything topped off in highsec. Maybe you can get away with 2 or 3 day cycle times. I don't know.
But, assuming once a day, that's still per character, not per account. It takes less than 5 minutes to click through and refresh everything, but logging in, switching characters, waiting for the game to load...it takes me about five minutes to do one character. Maybe you can averge faster than that. 5 minutes for three characters is nevertheless probably not realistic.
And that's only refreshing extractors, that doesn't include hauling time. If you're making high tier commodities you're going to need to be shuffling around goods between planets. Warp time alone is about a minute. If one character has to warp to 5 different planets, that's: log in, undock, warp to planet one, warp to planet 2, then 3, 4 then 5...then probably back to 1, then back to the PoS. That's ~7 minutes of warping, per character. That's not something you need to do every day, probably twice a week will be enough, but that's per character.
Assuming 5 minutes an account twice per day that's 24x10 or 4 hours.
But you still need to sell the product. That means getting it to market. Have you ever lived in a wormhole?
The title does say "possibly".
Well, again...go for it. Give it a try. Quick check of this thread, I could 8 yes responses and 3 maybe response.
But as someone who has done PI and spent some time in wormholes...rather than someone who has spoken to people who've done PI and been in wormholes...I think your time estimates might be off.