That's what "acronym" means. If you don't pronounce it as a word, it's not an acronym, it's just an abbreviation.
Interesting.
I've always thought of an acronym as an abbreviation formed from the initial letters of each word of a phrase, whether or not it was pronounced as a word or individual letters.
But it seems most formal definitions agree with you.
Most definitions of abbreviation use things like St. = Saint, Dr. = Doctor, etc., as examples. Not phrases.
What would you call BBC, DNA, OEM, USA?
Back on topic, DOS is pronounced as a word. I've NEVER heard anyone pronounce it as individual letters.
OS on the other hand, seems to be universally pronounced as individual letters. I've never had anyone ask me which "oss" I was running on my PC.