Kuketz - A german blogger/penttester is preparing an in depth review on GrapheneOs (he has already done it for the other alternative Operating Systems).
In his preparation he asked Daniel why no other devices are supported.
While the main reasons are well known to most of our community the answer from Daniel was very detailed.
So I just wanted to share the article if someone is interest.
While the article is in german, Daniels response is in english
https://www.kuketz-blog.de/weshalb-grapheneos-aktuell-nur-google-pixel-geraete-unterstuetzt/