Right, the customers who pay them to make the products they buy don't care. Why would they put the immense amount of effort and money into building something for people who are not their customers? Apple isn't a non-profit or a government program paid for by taxes.

Yes, Google's messengers were available everywhere because that's their business model. Google sells your eyeballs and is an advertising company. They're not messaging, they're not video, they're not even search - those are just products to support their actual business which is to sell ads. Ad companies by default benefit from being anywhere that people who have eyes are.

Apple is not an ad company, they sell hardware. They gain nothing from making something for free for other platforms. They make stuff that enhances their products and provide them a competitive advantage. Like, basically every company ever. They do make things occasionally for other platforms, but only when it actually makes sense. The iPod, for example, launched as a Mac-only product, because at launch they thought this was an accessory that would sell Macs. When it turned out the iPod was a runaway success, they built iTunes and the iTunes Store for Windows and opened up compatibility. In modern times, AppleTV+ or Apple Music launched as Apple-only services. Then they decided to move to other things, so you can now watch AppleTV+ on a Fire Stick or Vizio TV, and Music is on Android...

Apple on the other hand is known to intentionally make things incompatible with other brands.

This is simply false. Not making something for everyone is not the same as making it deliberately incompatible. Even the only actual examples of Apple choosing something deliberately incompatible is often a trade-off that where Apple (and usually their customers) decide the trade-off is worth losing compatibility. The largest example is Lightning, and when it was invented it was the best connector available. Even now, I'd make a lot of argument it's the best connector available, but the drop off to USB-C is no longer worth the trade-off of incompatibility. MagSafe (the MacBook kind) is another such, where Apple tried to drop their proprietary charger early in favor of USB-C and there was enough customer outcry they had to bring it back because it offers something USB-C does not.

Outside of these few rare examples, Apple actually has had to put in a large amount of effort in order to ensure compatibility. Most obvious example is things like working with Microsoft so Office would run on Macs, who actually do a lot of the things you claim about Apple. Through the 90s-2000s, MS couldn't even be counted on to keep compatibility between it's own Office versions so you'd be forced into buying a new license.

More relevant to today, Apple is the major reason why the web hasn't developed into just Google Chrome, and other standards-based browsers like Firefox can still exist. Fortunately Apple is large enough that as long as they continue to run their own browser and engine (Webkit, which they contribute heavily to open-source) the web can't simply fall into Google's hands. Which, is another example of actual deliberate incompatibility, as Chrome/Chromium tends to only follow standards when it feels like it. Or even more simply, just run Firefox and see how Google's products perform compared to just changing your user-agent. Or many other "chrome only" web apps. MS gave up and now runs Chromium, pretty much every other goddamn browser is Chromium based (Brave, Vivaldi, Arc, etc) and Firefox is now not relevant enough to stem the tide of Google. It's just Apple and the few billion iOS devices that are keeping the open web, well, open. Because as previously described, Apple is not an ad company, and their benefit comes in continuing to sell devices that their customers like, which means a good web browser that isn't spying on them.

Anyway, I'm out after this one. You can not like Apple or Google or whoever all you want, but best to stick to factual reasons that kind of make sense, at least. It's like, I have another tab open where people are trying to argue with a straight face that Google should basically just make Youtube, which costs billions a year to operate, totally free with no ads and no fees. I obviously am not a fan of Google (I actually kinda hope they took the advice, Google dying would be a good thing for the web and privacy in general) but do people not understand that companies exist to make money and are by definition not charities?