Java was never widely deployed on the web. The only services that ever used applets in any meaningful way were a handful of Asia-only banks. Applets were stillborn for a large number of reasons, all of which you can blame on Sun.
MS giving away IE for free torched Netscape's business model, but that seems like a strange objection - we all expect browsers to be free (and built into the OS) today.
In the case of WordPerfect, what I recall reading was that this was in small part because WP kept writing everything in pure assembly language for way too long, and in large part because MS gave Word a leg up with internal Windows APIs. This was raised in one of the antitrust suits against MS, but I don't recall which one. Either way, I had used a GUI WYSYWIG version of WordPerfect (for DOS) long before I'd ever even seen MS Word of any form.
Java was never widely deployed on the web.
This is a point that would have to be settled by numbers, and I don't have them. What I do know is that every simple web-based calculator app was written in Java, and that in my circles installing Java was one of the first things one did after installing Windows and a browser.
we all expect browsers to be free (and built into the OS) today.
I think this was a mistake. All that "you're a feature, not a product" nonsense is a distraction from the insane degree of consolidation we've tolerated in technology. There should be thousands of billion dollar tech companies each serving in interoperable niches, not a handful of trillion dollar tech companies.
Name one widely used (in the west) website that used Java applets. I can name exactly one, because I worked on the backend for it, but even in 2002 everyone knew it was an odd duck. Flash was still popular, activex still around, but ajax was a thing and everyone knew it was the future. Applets were a joke.
The market doesn't really care about your opinion of what is/isn't a mistake. Sorry.
Popcan was huge with multi-player games.
Microsoft gets no credit for these tactics.
The grandparent comment is right on the money with "You're assuming the goal of these things was to replace the product, when the goal was to destroy the competitor."
MS bought at least 10-15 years of dominance with EEE, vaporware, and other anticompetitive practices.
Just like Google killed RSS with Reader.
Just like Facebook bought WhatsApp and Instagram to avoid them potentially growing into replacements for Facebook.
The goal was to kill or delay an upstart that would distract users away from their core products, not to produce a successful competitor to the upstart.
Netscape
Netscape no doubt had its own problems, but MS deeply embedding IE into Windows 98 was a huge part of them.
Java
Actually Java was pretty dominant. Interactive web was either Flash or Java. If it was for entertainment, it was Flash, if it was for work or computation, it was Java.
Open/LibreOffice
Have you forgotten WordPerfect?