I feel like programming language designers should see themselves as quite beleaguered at the moment.
Even prior to full AI replacement, a properly trained AI will be able to take English language and effectively translate it to machine code, assembly code, or C code.
It doesn't really make much sense to have the human at the this layer for much longer.
The reason why these types of claims are baseless is because of the key fact that if AI tech stopped progressing right now, it's already a game-changer once companies adopt.
This is actually an interesting question that I also see in the AI art and artist debate. The trope is that "people thought AI would replace mundane jobs leaving room for creativity, now it's automating my creative job, why even bother making art?" The answer is the same as why anyone does any hobby at all. We still run despite making cars, ships, planes, rockets that go at hundreds of miles per hour. We still play chess and Go even though an AI can beat every human on the planet. We will still make music even if AI does simply because we want to.
Now, to expect to do a hobby as a job, forever (coding, art, music, whatever), that is a very privileged position to be in and most people in human history have not been that fortunate.
Point being that traditional stylesheet based CSS is all but obsolete now. Any dev can pick one of ten thousand component libraries, slap a few utility classes on the element, and call it good enough.
Swift currently supports Linux and has unofficial support for Windows. It's open-source and compiles via LLVM. Commercially Apple has been unenthusiastic about fleshing out its support for non-Apple platforms, but the open-source community has partly filled that gap and there's lots of enthusiasm in the community. Given the recent decline in Apple's hardware sales, they could be heading for a Microsoft-like rebirth into a company that's forced to play nicer with others.
There is almost zero application for Swift outside of an Apple environment. I'm willing to bet there is precisely zero production code written in Swift for Windows (or Linux).
Anyhow, the Windows API (.net, C#) is better and has a brighter future and present.
Like I said, Windows support is currently middling. I would bet there's some Linux production code in Swift, though not much. But both of these are cultural problems, not technical ones. If Apple said tomorrow, "we're going to go all-in on making Swift a universal programming language", thousands of developers would cheer and jump on-board. The main thing holding it back right now is lack of confidence in its support; people don't want to invest in a new cross-platform codebase that might have its legs cut out from under it in a couple of years.
Swift is much closer to the metal than .NET, and it has very innovative syntax features. It's more analogous to Rust than to C#. .NET is a strong cross-platform ecosystem, but it's silly to say "we don't need any others because this one's good enough". It's not even the strongest one that currently exists - probably the JVM is. It honestly just sounds like you're hating on Apple for the sake of it.
Superficially it has a lot in common with JavaScript (really, TypeScript), but like Rust it compiles to a native binary and doesn't need a runtime environment (C# and Java do). Also like Rust, it frees the user from manually managing memory, despite lacking a garbage collector. This combination of features makes both languages very exciting. I'm not aware of any others right now that can claim the same.
I also haven't heard of it being outperformed by Java and C#; do you have a source for that claim?
The book iOS and macOS Performance Tuning ( https://www.amazon.com/iOS-macOS-Performance-Tuning-Objectiv... ) has pretty damning benchmarks against Swift versus Objective-C even without using any tricky optimizations (not what you originally asked but something to consider). Of course the whole book (written by a former Apple engineer IIRC) is pretty much full of performance gotchas across many Apple frameworks/APIs, but the chapter on Swift was pretty harsh and basically said Swift fails to live up to its name versus Objective-C (at least at the time the book was written).
I think most people think that Swift performs like Rust/C++/C since it doesn't have a garbage collector and imagine ARC is providing relatively free memory management, but it seems Swift performs closer to languages with a garbage collector due to the various design constraints on the language (interoperability with Objective-C, ARC isn't free, and maybe without the explicit lifetime/ownership declarations in the code like Rust, ARC can't be optimized as well).
GPT-4 performs quite well on reasoning and critical thinking assessments.