Judging from questions like why dont Apple buy TSMC or built their own foundry I would guess a lot more context will be needed and it would be at least a few thousands words if not more.

But to put it short, and one point that is not pointed out enough. TSMC has always been the leading edge foundry for nearly all SemiConductor company apart from Intel and AMD. If you want the most advance third party foundry, you basically only have TSMC to choose from. That has been the case since at least 2008. ( Or arguably a lot longer ). So for pretty much everyone in the industry nothing much has changed. TSMC mapped out their roadmap, speak to a few key client on their needs and capacity, plan their investment and ROI accordingly. The only thing that had changed is that they somehow not only are the leading edge on Foundry services, but also leading in terms All Silicon producer, where Intel used to be the king. So one way to think about it, is that TSMC has been executing like clock work for the past 20+ years. While Intel has multiple minor slip and one major slip in terms of node process, and also completely missed out on Smartphone revolution which provided an additional 2 Billion+ consumer electronics market using silicon chips, and they didn't get to enjoy the amortization over those potential 2 Billions unit volume. Even if they did like the 200M Apple Modem order, they completely failed to plan the CAPEX and OPEX spending and capacity planning. Which was later confirmed Intel's CEO Bob Swan. ( Not his fault. It was all on Brian Krzanich ). So to answer your question. "how they are advancing too fast while Intel (also AMD?) are "stagnated"?"

It was't TSMC moving too fast. It was Intel completely fucked it up. I wrote a lot about how Intel should have done Foundry in 2011 and how they missed everything by 2014. But a lot of these were only obvious now. Some of my comments below from 2016 and 2020.

Edit: That doesn't mean I am negative on current Intel. I was so happy and cried when Pat Gelsinger got back to Intel as CEO. It is a tough battle. But if Pat dont make it work then I doubt anyone else could either.

Copying what I wrote in 2020 [1]

>Tl;DR, It is TSMC, not Apple.

I have been thinking starting a blog on the topic considering how often this question keeps popping up. From a very high level overview.

1. Apple is partnering with TSMC. TSMC is now the leader in leading edge semiconductor manufacturing. A title that used to belong to Intel.

2. TSMC is now a generation ahead of Intel, meaning those thermal efficiency you see comes from using a better node. Nothing much to do with ARM or x86.

3. Both ARM and TSMC has dramatically change the Industry, you can now buy Designs / Blueprints from ARM, ( Or any other IP vendors such as Img PowerVR ) and Fab ( meaning producing them ) them with a Foundry.

4. TSMC is a Pure Play Foundry, meaning the Foundry does not produce their own chip and sell in the market to compete with its customers. A Non Pure Play Example would be Samsung or Intel, where Samsung produce their own Mobile SoC Exynos, and Intel with their x86 Chip. If you were Qualcomm producing your chip in Samsung's Fab, you are directly competing with them.

5. Apple now has the volume, or economy of scale to produce CPU themselves. Apple makes more silicon in unit volume than Intel per year.

Another Comments I wrote in 2016 [2]

> These process, R&D, process optimization, materials science are all cover by their cost to TSMC / Samsung. Btw TSMC's 2016 Capex ( including R&D ) is now equal to Intel $9.5B. When you consider TSMC is Pure Play and Intel being IDM, this is very significant mile stone.

[1] https://news.ycombinator.com/item?id=23822834

[2] https://news.ycombinator.com/item?id=12947327