The Martin in question is owned by my uncle. Barely ever plays it - maybe once every two years - so it's got zero wear and tear. He keeps it in a very expensive case in his closet. He's a multimillionaire and bought it as a bit of a status symbol, so we're not talking a low-end model. Never got wet and never got handled enough to be mistreated.
That trade I mentioned was offered to me 20 years ago when the Martin was nearly brand new, and in the years since I've visited him on occasion and played it. It's still in pristine shape.
It's not a bad guitar per se. There's just nothing special about it.
I still have the Takamine as well. The Takamine has gotten wet - I've played it in the rain. It's been handled and played so much the fingerboard is top to bottom covered in wear spots. There's a dent in it and I've accidentally banged it into things a few times over the years. It's been restringed so many times that I had to replace the tuning pegs from wear as well.
It still has the same magical tone that it had back then.
Whether you compared the two guitars side by side 20 years ago, 10 years ago, or today, the Takamine has always had the superior sound.
I simply lucked out and picked up a masterpiece guitar, and he didn't luck out and got just another guitar off the line which was nothing special.