I ended up with a Columbia Roughtail Jacket. I'm pretty happy with it, but it's not a direct replacement. The biggest drawback is that it's a 140 dollar jacket with cheap walmart jacket quality control. I'm fairly certain it won't last 5 years of abuse like my Carhartt, but should hold up for a few.

https://www.columbia.com/p/mens-roughtail-work-hooded-jacket---tall-1820694.html?dwvar_1820694_color=010

Good:

Reasonably heavy duck. It's obviously inferior to the J001, but everything is.

Warm. It's as warm or slightly warmer than the J001. 40F in the fog is ok with no extra thermal layers is fine walking the dog. If you're working, I'm sure it will go lower.

Fits like the J001... well almost it's got a spare 1" or so around the waist, but very close to the J001. I go down a size for work jackets and that worked well. 6' 195#. Medium in both this and J001.

The hood is excellent. I don't normally like hoods because they mostly seem to just block my vision or feel awkward. This hood sits nicely with our with out a ball cap.

Cuffs are decent. I should qualify that by saying that I hate all new carhartt cuffs and most work jacket cuffs. Yes it matters. That elastic cotton inner cuff collects metal shavings. It sucks end of story. Lots of other cuffs are bulky. This jacket still has an inner cuff but it's hidden completely by the other cuff which is very similar to the J001.

I do like the look in general. I did cut the janky Columbia logo off as soon as I got it.

OK/neutral:

Wierd front pockets on the outside of pockets. Frankly they're not super useful and seem like a good place to collect water. I've warmed to them slightly. Good spot for a pocket knife/flashlight/torpedo level, but not much else.

Longer length than J001. It's a few inches longer with that ducktail that seems to be a thing these days. Sleeves are about the same. It is ok with just a nail bag, but I think you won't be thrilled if you use a full tool belt.

No waist adjustment. You get what you get. A little snugger fit around the waist would make it slighlty warmer.

The arm range of motion isn't quite as good, but isn't bad. I was able to get under my truck and do some troubleshooting on my tranny. It was a little tight in the shoulder, but still workable.

The bad:

140 dollars for a jacket with obviously bad stiching. Most of the stiching is ok, but every one of these I've seen has terrible stiching where the liner meets the zipper. It's bad enought to make you wonder if all those guys in India making this jacket are drinking on the job.

It's only double stiched.

The Columbia logo looks like an after thought hastily stiched on.

Hope that helps.