If perfect spelling/grammar was so easy to have the moment "personal computers became a thing", then why do my eyes bleed trying to read what people write onlin

If perfect spelling/grammar was so easy to have the moment "personal computers became a thing", then why do my eyes bleed trying to read what people write online every day? We've had near-flawless spellcheck for years now. I think maybe it's not as much of a useless skill as you think it might be...