It's probably just that the product is not flawed, it's just very niche. Even I think spending more than $200 for a gaming cpu is stupid but apparently it's a market.
It's not a bad general cpu outside of gaming either and why would he be so hung up about overclocking but not mention amd's old statemend of something like "all ryzen am4 cpus are overclockable" which is now no longer true and that the market hasn't demanded overclocking for consumer cpus since intel locked away their K series.
All of charlie's recent articles (that I can read for free) have nose dived in quality and are petulant rants. It's good that he's calling these things out but it's done in a less professional manner or as impartially from what I would have expected of him from years past.
He seems to think that the lack of overclocking is due to thermal stability; that is, the bond between die can’t take the higher heat. This doesn’t really seem that likely to me. The denser process used for the cache die probably has a lower voltage limit than the high performance process used for the cpu, so the reason given is likely at least partially true. It is also more likely to have reduced life span from electro-migration at higher temperatures and higher voltages. Any kind of stacking does require a lot of engineering due to differing thermal expansion rates, so it is of concern, but anything so new is of concern.
I don’t think they are actually bonded by heating at all as Charlie mentions. It seems to be a cold weld. Metals will weld themselves together in a vacuum. Most things are held together by “just” Van Der Whaals forces; otherwise, everything would be one giant molecule. It would technically be a metallic bond, not just Van Der Whaals forces, although I don’t know if silicon participates in metallic bonds; any chemist around? The copper will cold weld together though. It is also probably surrounded by an epoxy for the packaging such that it cannot move.
The heat issue is that the cache will produce some heat of its own. This raises the temperature above the compute die. Heat transfer is proportional to the temperature difference, so this reduces the heat transfer, even if the thermal conductivity through the material and interfaces is roughly the same. I don’t think the thermal interfaces between the stacked die are an issue. The die are polished down to exceptional flatness. I think it will really behave like one piece of material. The copper TSVs may actually increase thermal conductivity over a device without it. The increased heat / lower thermal transfer could be gotten around by using a TEC, as in the AMD patent I posted about. That had top memory die that would be in more direct contact with the heat sink. The TEC layer would be in between the memory die and the bottom logic die(s), probably just to provide a slightly higher temperature differential to aid in heat transfer.
I think a lot of enthusiast over estimate the number of people that overclock. It was much better long ago when the differentiation between parts was often just clock speed. Look at the early Nehalem based extreme edition parts. It was ridiculously expensive just for higher clock. Now, with boost clocks and thermal limit settings, how often does anyone actually overclock? The boost clocks already are a kind of overclocking.
Also, the top end is always at a very high price to performance ratio. Is it a niche part? Yes, but so are just about any other high end processor. Most people don’t spend over $200 on their processors just like most people don’t have a 3090 gpu. A lot of people have a 3060 and maybe a 3070 though. This is a little more niche in that it mostly only makes sense as an upgrade part. I don’t see it as any more of a marketing part than any other high end part. A 3090 is mostly a marketing part; people see it at the top of the performance charts and all of the reviewer using it and then go buy a 3060.