I have asked this question to myself many times. Today I finally realized why.
I just wonder what people think about it.

I strongly believe everything Satoshi did in bitcoin protocol code and whitepaper, he did for a reason.
Satoshi spent around 2 years on designing the architecture of the network, everything he was explaining was meaningful.
For protocol is set in stone he was referring the core design which is described in whitepaper.

So, I am curious of what people think about 10 minutes block time.