> GrapheneOS currently has half a million users and growing

That is a total install base right? Unless all 500k of them are upgrading yearly, this number is miniscule. You are underestimating the R&D required to put out a new phone each year only to have 30% (high estimate) of users buying it. That's 150k devices, which is not worth any volume.

For a smaller manufacturer (e.g. Fairphone), that may mean a lot. If I remember correctly in 2021 Fairphone was selling 100k phones per year?

Also I am genuinely interested: is it that hard to meet GrapheneOS' requirements? Feels like it shouldn't take years of R&D for every new iteration. And also that it's about getting the right deals with the suppliers, which is not really an R&D issue?