From TSMC's perspective, the entry level market isn't where they make their money. You can make entry level devices on old processes that have a lot of competition. It would be really bad for TSMC if Apple were to monopolize the high end of the market, because that's what uses the advanced process nodes TSMC makes its money from.
> Then, Apple gets a temporary exclusivity on the new node (which they helped finance), but this leaves a lot of capacity on the older nodes. These processes are still really good, the vast majority of TSMC customers don’t care about being on the bleeding edge for the sake of it.
Except that they do care, because they're competing in the same market. Apple is currently making a lot of hay out of the fact that the M1 is more power efficient than PC laptops, which is attributable in no small part to the fact that they're on TSMC 5nm when everyone else is on TSMC 7nm or worse.
If nobody was on the newest node, or Apple was making products that didn't compete with AMD/Qualcomm/Nvidia/Intel in the market, the others not having it wouldn't matter. When the device customer is going to prefer the best one, and the one on the best node has an advantage, it does.
> what would have been the alternative for TSMC?
If Apple isn't signing some kind of exclusivity deal requiring TSMC to give all of its new capacity to Apple, build more of it using their own money so that when it comes online, there is enough for more than Apple. If they are demanding exclusivity, inform antitrust authorities of this.
> What is the end game you’re afraid of? Apple takes its business elsewhere?
Suppose Apple monopolizes the high end market. They take 75% of it using the process advantage, then take the rest as the network effect from that crushes alternatives. They're now your only customer for the newest process nodes, so they squeeze your margins to zero. At the same time, they buy Global Foundries and pour money into it until their process is better than yours, and you no longer have the money to compete because you let all your other high end customers be destroyed.
It's what Apple did to Imagination Technologies and tried to do to Samsung.
Similarly intels process issues showed up when they started trying to make xeon before the desktop processors.
Then, Apple gets a temporary exclusivity on the new node (which they helped finance), but this leaves a lot of capacity on the older nodes. These processes are still really good, the vast majority of TSMC customers don’t care about being on the bleeding edge for the sake of it.
Let’s be realistic: what would have been the alternative for TSMC? Leave Apple’s investment out of the table and waste time bringing their new process online without it? AMD or Qualcomm would not be in a much better position right now. Or TSMC, for that matter.
What is the end game you’re afraid of? Apple takes its business elsewhere? To whom? Wouldn’t this leave TSMC with paid-for facilities they could now use to produce chips for other customers at a discount?