And modern X86 chips are in fact NOT 64 bit anymore, but hybrids that handle tasks with 256 bits routinely, and some even with 512 bits, with instruction extensions that have become standard on both Intel and AMD

On a note of technical correctness: That's not what the bitwidth of a CPU is about.

By your account a 386DX would be an 80-bit CPU because it could handle 80-bit floats natively, and the MOS6502 (of C64 fame) a 16-bit processor because it could add two 16-bit integers. Or maybe 32 bits because it could multiply two 16-bit numbers into a 32-bit result?

In reality the MOS6502 is considered an 8-bit CPU, and the 386 a 32-bit one. The "why" gets more complicated, though: The 6502 had a 16 bit address bus and 8 bit data bus, the 368DX a 32 bit address and data bus, the 368SX a 32 bit address bus and 16 bit external data bus.

Or, differently put: Somewhere around the time of the fall of the 8 bit home computer the common understanding of "x-bit CPU" switched from data bus width to address bus width.

...as, not to make this too easy, understood by the instruction set, not the CPU itself: Modern 64 bit processors use pointers which are 64 bit wide, but their address buses usually are narrower. x86_64 only requires 48 bits to be actually usable, the left-over bits are required to be either all ones or all zeroes (enforced by hardware to keep people from bit-hacking and causing forwards compatibility issues, 1/0 IIRC distinguishes between user vs. kernel memory mappings it's been a while since I read the architecture manual). Addressable physical memory might even be lower, again IIRC. 2^48^B are 256TiB no desktop system can fit that much, and I doubt the processors in there could address it.

Intel was all about market segmentation

See also: ECC memory.

It was also a big surprise when Intel just gave up. The industry was getting settled in for a David v Goliath battle, and then Goliath said this David kid was right.

I hated that you had to choose, virtualization or overclocking so much. Among a lot of other forced limitation crap from intel.

A bit like cheap mobile phones had a too small ssd and buying one at least "normal" sized bumped everything else (camera, cpu, etc) up too, including price ofc.

I expect them to merge enthusiast into the pro segment: It doesn't make sense for them to have large RDNA cards because there's too few customers just as it doesn't make sense for them to make small CDNA cards but in the future there's only going to be UDNA and the high end of gaming and the low end of professional will overlap.

I very much doubt they're going to do compute-only cards as then you're losing sales to people wanting a (maybe overly beefy) CAD or Blender or whatever workstation, just to save on some DP connectors. Segmenting the market only makes sense when you're a (quasi-) monopolist and want to abuse that situation, that is, if you're nvidia.

They honestly seem to be done with high-end "enthusiast" GPUs. There is probably more money/potential for iGPUs and low/middle level products optimized for laptops.

I don't see this happening with both consoles using AMD, honestly I could see Nvidia going less hard on graphics and pushing more towards AI and other related stuff, and with the leaked prices for the 5000s they are going to price themselves out of the market

Even successful companies themselves take care in not putting all eggs in one basket on anything they do. Having alternatives is a life saver. We should ensure that we have alternatives too.

Lack of competition results in complacency and stagnation.

This is absolutely true, but it wasn't the case regarding 64 bit x86. It was a very bad miscalculation, where Intel wanted bigger more profitable server marketshare.
So Intel was extremely busy with profit maximization, so they wanted to sell Itanium for servers, and keep the x86 for personal computers.

The result was of course that X86 32 bit couldn't compete when AMD made it 64bit, and Itanium failed despite HP-Compaq killing the worlds fastest CPU at the time the DEC Alpha, because they wanted to jump on Itanium instead. But the Itanium frankly was an awful CPU based on an idea they couldn't get to work properly.

This was not complacency, and it was not stagnation in the way that Intel made actually real new products and tried to be innovative, but with the problem that the product sucked and was too expensive for what it offered.

Why the Alpha was never brought back, I don't understand? As mentioned it was AFAIK the worlds fastest CPU when it was discontinued?

This is not entirely fair, Kodak invested a lot in digital photography, I personally bought a $1500 Kodak digital camera around 2002.
But Kodak could not compete with Canon and other Japanese makers.

To claim Kodak could have made more successful cameras earlier, is ignoring the fact that the technology to make the sensors simply wasn't good enough early on, and would never have been an instant hit for whoever came first to market. Early cameras lacked badly in light sensitivity dynamics and sharpness/resolution. This was due to limitations in even world leading CMOS production capabilities back then, it simply wasn't good enough, and to claim Kodak should have had the capability to leapfrog everybody doesn't make it true.

To claim Kodak could have beat for instance Canon and Sony, is ignoring the fact that those were companies with way more experience in the technologies required to refine digital photography.

Even with the advantage of hindsight, I don't really see a path that would have rescued Kodak. Just like typesetting is dead, and there is no obvious path how a typesetting company could have survived.

The concept you are describing is called Innovator's Dilemma and imo the most recent example for it happening is with legacy car manufacturers missing the ev transition, because it would eat into their margins from ICE. But i am not sure if this is a good example for it.

However imo it seems like a great example for what Steve Jobs describes in this video about the failure of Xerox. Namely that in a monopoly position marketing people drive product people out of the decision making forums. Which seems exactly the case here where the concerns of an engineer were overruled by the higher ups, because it didn't fit within their product segmentation.