That it was successfully completed and the tech provides a better basis for future features? Sometimes timeframe and team size are almost irrelevant to the success of a rewrite project.
Not saying that time and money is unimportant, but sometimes time and money are the soft(er) constraints. Extreme example: the toolchain is lost and the original application can not be built anymore, but the business currently swims in money.
I am definitely not saying that adding that good stuff to the existing app incrementally was impossible. They could have done that. But for "strategic" reasons, the stakeholders wanted to replatform, and we did that.
That it was successfully completed and the tech provides a better basis for future features? Sometimes timeframe and team size are almost irrelevant to the success of a rewrite project.