alt Hacker News> The real advantage is knowing exactly what Apple is launching months or years in advance, because that can inform strategic planning.
While I'm sure some level of internal leakage does take place, at least on paper the fab's planning needs to be firewalled off from their own chip roadmap.
I'm also not sure how much Apple actually cares, tbh. Yes, they currently have an edge in silicon, but it's heavily due to being willing to outspend everyone else, and their real superpower is vertical integration - which Intel isn't in a position to compete with.
I think Apple doesn't really have a choice. They've been very strongly encouraged by the current US government to move as much chip manufacturing to the US as possible, and particularly to make Intel Foundry work, or face... problems.
Also the AI boom means NVIDIA et al. can afford to buy TSMC's best processes at scale, which means less available capacity for Apple.
I'm sure given no other forces at work, Apple would prefer to stick with what they were doing previously, buying the lion's share of TSMC's best process.