I didn't claim that Linus came up with the design from scratch, nor that git was less experimental than monotone in 2005. Just that no one used monotone, so git was not a reduction in safety/assurance compared to any in-use SCM. And as mentioned, it's goal was speed, not cryptographic assurance.

I also was surprised that git became so popular, I thought mercurial would win for "ease of use". But I've never been an advocate or influencer of popularity. I think that's mostly due to GitHub, which got it to a market-share tipping point.