Hi MJD
According to Korea's local magazine, JLP shipped 150k in 1996 (article in 11/12/1996). Although catalog sales may be tiny, it would also end up a bit higher than 150k, right? Also, Falling Into you (Korean name: Because You Loved Me) shipped 300k in 1996 according the the same article, and Let's Talk About Love shipped 310k in 1998 (article in 11/12/1998). Maybe you already have some of these figures, what is your eventual estimates for these albums there?

Music Box by Mariah Carey actually reached 1 million in South Korea by 11/12/1996.The same article that onfirmed Daydream sold 600k, Because You Love Me sold 300k, JLP sold 150k, etc. Other articles also can be found on chosun.com.
http://m.chosun.com/svc/article.html?sname=news&contid=1996121170222

No doubt higher than 150k then! On their communication listing all her sales awards, it was shown as Platinum in SK, so anything from 100k to 200k, while Supposed missed Gold the status, so 150k was the safest estimate to avoid large errors, but it seems that it sold a bit more.

Alanis Morissette announces new album. 'Such Pretty Forks in the Road' will be released on May 1, 2020'. I would really like to see a major turnaround happening for Alanis.

2020 is the year Alanis will release her first studio album in 8 years. It also marks the 25th anniversary of her breakthrough smash album "Jagged Little Pill".

Looking at Spotify the album still holds up well:

All I Really Want - 16.8M
You Oughta Know - 99.2M
Perfect - 9.0M
Hand In My Pocket - 78.8M
Right Through You - 9.4M
Forgiven - 7.1M
You Learn - 61.3M
Head Over Feet - 51.5M
Mary Jane - 7.0M
Ironic - 205.9M
Not the Doctor - 7.3M
Wake Up - 5.1M
Your House - 7.2M

Total - 565.7M

The big one is obviously "Ironic" with over 200M plays on Spotify. But the entire album does well with all 13 tracks above the 5M mark and no less than 5 tracks over 50M!

The bad news is that those 5 tracks are also the top 5 of her entire career with no other songs above 50M. In fact 12 of the 13 tracks on "Jagged Little Pill" are in her top 20 (and "Wake Up" is #21)!

Her other (non-JLP) top 20 tracks:

Thank U - 45.5M
Uninvited - 24.1M
Hands Clean - 18.5M
That I Would Be Good - 10.1M
Crazy - 9.9M
Guardian - 6.9M
Everything - 5.9M
King of Pain - 5.8M

Let's see what the new era brings.

What went wrong?
In one way I think the author is correct. Alanis is not exactly a media obsessed diva and her career path looks pretty similar to another media shy diva who had a huge debut but inconsistent follow ups, like Tracy Chapman.
However I personally think it's not the only reason for her fast decline. I think that both "Supposed Former Infatuation Junkie" and "Under Rug Swept" could have been more succesful if handled differently with a different choice of singles. Per example I'll never understand why they didn't use "Uninvited" as the lead single of "Supposed..." and why they stop releasing more singles from "Under Rug Swept" after "Precious Illusions" bombed. I like those albums a lot and I think both those albums deserved better results but a series of poor choices led to both albums underperformance and lead to Alanis being labelled as a one album wonder. Pity cause I think she deserved a better career and I think that her catalog is full of good tunes besides "Jagged Little Pill"

Great article! It's a shame Alanis hasn't seen much success after Supposed Former Infatuation Junkie, it's also very curious and impressive how much Jagged Little Pill still stands up the test of time. I'm curious to see if her new album will, at least, generate higher numbers than Havoc and Bright Lights. I'd love to, it's a very good album!

On a sidenote: can you analyze Nelly Furtado's career? Considering she went indie a few years ago I think it'd be an interesting study case.

Alanis’s Uninvited sold 7 M copies by Dec 31, 1999, according to Billboard’s Decade end publication.

They listed this among other accomplishments Bc JLPill is the #1 album of the 90’s BBoard H200 decade-end list.

https://books.google.com/books?id=9w0EAAAAMBAJ&pg=RA1-PA4#v=onepage&q&f=false

Page 15.

It also lists her MTV unplugged album at 1.5 M “and climbing”.

Since this is the 90’s, these sales are pure, pre-streaming, and updated 23.5 years ago… so plenty of time for you to have read the old numbers.

Yet you didn’t even mention Uninvited on your Physical singles listing…

7 million seems waaaaay too high, as it has no certification. And Unplugged is listed here with 3,3 million pure sales. Why is that not correct in your view?

Who cares. She did art the way she wanted. That's what mattered to her and her followers.