A比B+形容词

比 already does the comparing, so adding 很 makes the whole phrase sound doubled and wrong. In a 比 sentence, the descriptive word stands alone without extra strength words: 他比我高. That is why 他比我很高 fails, even though 他很高 works fine by itself.

Chinese puts 比 before the descriptive word: A 比 B plus the descriptive word. English does the opposite, saying 'taller than me' with 'than' after the word. If you copy English order, you produce 他高比我, which sounds broken to native ears. The story sentence shows the correct order: “有的时候，老电影比现在的新电影有意思。” ── [《你喜欢看老电影吗？》](/read/do-you-like-old-movies#s16).

To say 'not taller than', Chinese uses 没有: 我没有他高. Saying 我比他不高 sounds like you are trying to block the comparison instead of making it. In a simple 比 sentence, 不 before the descriptive word is not the normal negative form. Use 没有 plus B plus the descriptive word for this meaning.