Thomas Ptacek leaves Fly.io and argues the operating system's isolation model no longer fits single-user software

Sources: primary, discussion
Summary: The post, dated 2026-09-25, opens by stating that the author is parting company with Fly.io and that he is talking his book. Its argument is that process isolation exists to partition software imported from strangers, so it earns less on a device where most applications share one author. That he is launching a phone built on that premise comes about two thirds in, after the argument.
Why it matters: The design claim arrives with a disclosed commercial interest, so the argument and the product resting on it have to be read together.