What I have seen is that devs start fulltime at the office and as they gain experience at the company and the trust level builds, then they start working remote

What I have seen is that devs start fulltime at the office and as they gain experience at the company and the trust level builds, then they start working remotely a couple days a week. Some people become indispensible and then want to move and the company will cut a 100% remote deal in order to retain their services. This is really the only way I have seen it work out such that the person maintains any kind of job security.