Jim Slade

I can read it in the latest version of infinity without crashing.

That would be layout (largely justification) based upon the entire paragraph, rather than line-by-line. LaTex has done that forever. InDesign does it. But most don't. 
Justified Word documents look funky because it justifies by line by inserting space. 
Beyond better look, a benefit of paragraph composition is that relatively small paragraphs do not cause the paragraph length to change much. If you have a document with manual references (e.g. legal work with a table of authorities), fixing a few characters in a document does not cause much text shifting to pages that throws you references off.
 

Is there any news on potential updates? I bought Publishers in the hope that books spread across multiple files would become available soon. I have not been able to use Publisher at all because, when I try to load the 400 pages with illustrations, Publisher says it's out of resources and crashes.

Try the APh Denoise filters ...

I add couple more:
1. The ability to split books into multiple files. My books I have exported get a resource error when I try to import them into Publisher. (as urgent as footnotes).
2. Paragraph composition. 

To merge from several separate source files; not to combine files into one big one. When I try to import my separate book files, I get a lack of resources dialog box then publisher crashes.

I give up. If no one gives a wet fart around here about how Publisher could fill the needs of the market, it never it going to (e.g. footnotes). The publishing community needs to look to someone else then

Footnotes are essential for legal publishing as well. Nearly every sentences gets a footnote.

Having refused to join Adobe's subscription scam, I have been trying to replace my aging creative suite. I was successful with Affinity Photo (thank you very much).
My documents tend to have a lot of footnotes/end notes. Last I checked, Publisher did not support this (beyond what ancient Adobe did). I thought I would check in and see if footnotes have been implemented yet so I can cross another Adobe product off my list.

The default Word Templates are a total joke. I get the impression the do things just because they can be done. Who uses superscript ordinals besides "for sale" signs in used car lots? Blue headings? 
I who was the idiot who came up with themes that are just half-assed template.
I switched to Word from what by then was Ami Pro and it was a major step downward (a book publisher demanded that). I had used Word for Windoze since WIndoze 3 in the early 1990's for work. There is been little improvement in Word since I first used it.
Word has needed for 30 years:
1. Templates with the 10 styles actually needed in to the document; not ever one of the 2.987 million default styles.
2. Reasonable justification.  You can tell if any justified document has come from Word because of the rivers.
3. Hyphenation that follow basic hyphenation rules.
4. Better support for alignment (vertical and horizontal) without having to mess with Word settings.
5. Distinction between character and paragraph styles. If you click on text you should be able to see both in use.
As the evil empire gets more people to subscribe word improvements are less likely. Just as improvements in Adobe products have come to an effective halt now that they use subscriptions. (And Quark has been totally FUed as a company.)
For my own copies, I don't upgrade word until it no longer functions on my OS. That is usually ten years. My last word upgrade (11 year ago) brought me open type features and nothing else. If I "upgrade" now I but I'd just get a change in UI.
 
 

Hopefully, this is not getting off topic but another critical need is a decent word processor.
"What do you mean by decent?"
Glad you asked. Some of the features of a decent word processors would include:
decent text justification that operates by paragraph, rather than by line and does not leave gaping spaces. hyphenation that follows the rules of hyphenation (and maybe even was configurable) and does not automatically break a hyphens. (e.g., "4-F" should not not break even with a hyphen and "A–Z" should not break with an en dash). Be able to define ranges of characters with no break (character style setting) Be style based and have styles easy to use. Not having 57.358 million pre-defined system styles that cannot be deleted so that you have to sort through a monster list to find the 10 styles you need for your template; be able to define style hierarchies in session and not have to go through the total BS of formatting text you want then define styles from already formatted text. Have character and paragraph styles independent. No BS hybrid styles that are a mixtures of the two. Have the both the paragraph and character style displayed when you select text. Have an easy method of removing character styles. Allow rounded corners on text frames. Be able to easily identify text that has been manually formatted by the idiot coworker who refuses to learn how to use styles. Full font feature support Be able to format all the elements of a numbered or bulleted list. In other words, a full featured work processor without the bloatware.
Now that the "leading" Word processor (the one that has seen virtually no functional improvements in 25 years and where each "upgrade" is little more than a change in user interface) is pushing the subscription scam, the market there should be opening up.
Monopoly and subscription models are two biggest poxes on software progress.
The "leading" Word processor has had for decades a Table of Authorities feature that has never been usable. It was probably added as a check the box feature for a government contract. The vendor has never made any effort to make that feature work.
 

Footnotes are essential for legal publishing as well. Nearly every sentences gets a footnote.

Footnotes are essential for legal publishing as well. Nearly every sentences gets a footnote.