Yeah, that's how businesses work. Just because a company is a billion dollar company, doesn't mean they can give things away for free.
Last I checked, they're still a company that runs on losses. Seems to me, they pretty much need the money. Seems like you're the one who needs a reality check. Imagine, people walk in to wherever you work, and just because your place of employment makes millions if not billions, ask for free stuff? And then you give it to them for years, eventually asking money for a few things, all the while, still giving things out for free, and they complain that you shouldn't charge money because you already make money.
Besides, even in the Software industry, pricing can be different. There is a cost associated with product development. Softwares like games, where you expect millions of people to buy your product, you can price it at $60. That doesn't mean a niche software like Fusion360 can follow the pricing. It's fine if you don't want to pay that money, just know this, eventually it wouldn't make sense for them to continue making this software and they will shut it down.
They're charging an entry fee where there wasn't one before. They want your money, and decided this was a good way to get it from a userbase they already had cultivated. They aren't going to pay their software engineers more money or any of that, they aren't going to make Fusion 360 more "sustainable", they could do that overnight with the cash they have, so all of that stuff about "software engineers have families" isn't actually relevant in the slightest, that's just a scapegoat corporate wants you to believe in. They're just trying to get more money. It's that simple and has absolutely nothing to do with the product. If you can't see or understand why people might be irritated by that (an entry fee where none existed prior and where it's mostly just making billion dollar corporations richer than they already are), I suggest you try actually looking at the state of the world around you for once in your life.