That might be typical but it's not necessary.
Yet, deaf children "without access to sound" do learn to read and write, even if it's not "from the spoken form," and they can do it without an artificial code system.
Let me put it another way.
English-speaking people can learn ASL in a voice-off class without using an intermediate artificial code (such as SEE), and without any prior exposure to sign language. My first level of ASL was taught to me by a Deaf instructor, voice-off, all with visual references. And I don't mean just writing a list of words on the board and showing sign equivalents.
English is not Greek/Chinese/Swahili/whatever. English does NOT use the same alphabet or grammar as many other languages, yet English-speaking people learn those other languages without creating "codes" for the process.
Honestly, I don't know why anyone would want to make the language learning process any more difficult than it is.