Ok? I didn't say all natives make such mistakes, it's just that they're substantially more prone to make them, "by design". Non-natives will make various spelling mistakes too, just of different sorts, rarely those based on homophones.

“Learning by ear” is just another excuse for laziness and/or ignorance

But that's how every native language is learned, it's not "laziness". You listen to your parents and learn to speak years before you develop usable reading abilities. Writing is learned afterwards, and largely bases itself on your knowledge of the oral form of the language. This applies to any language written in an alphabet (i.e. disregarding Chinese and similar).

Pick up books, read extensively, and like anyone else not marinating in cultivated ignorance, you too can utilize the language effectively and correctly.

If this humble advice is directed at me - thanks a lot, but we've been talking about native English speakers, which I am not.