No one is going to live in it. Like the most expensive art, the one-of-a-kind nature of this property is what makes it attractive (for investment purposes).
Plywood, despite its low-brow demeanor, is far more suited to flexing than hard teak wood.
If we're talking boats, on the other hand, then teak is the clear winner.
I'm not so worried about earthquake performance because as long as you way, way over engineer you should be fine. The 3" teak isn't for strength (that's what steel is for) it's just so that it looks very solid.
For $500mm I would expect a safety factor in the high single digits. I know that's not what this house is about so I know it's not there, but I can't help but be an engineer.
You can buy 200 year old teak. There are plenty of wooden buildings around the world that are multiple hundreds of years old.
When plywood is shown to last 500 years without breaking a sweat, then I'll believe it's a great building material full stop.
For $500mm it should be built to last a millenia. I know it's not, but again, engineer brain.
I think it's unlikely you'll need it to last that long.
Isn't it a little strange to be comparing plywood with 3" teak? Can you even get sheets of teak that aren't a veneer? Wouldn't LVLs or glulams be a more apt comparison?