This only applies now because fundamental aspects of a competent modern language are still being added - it was only recent that you could have a const fn at all, async is only coming at the end of the year, there are still no HKTs, etc.
I'd be willing to bet Rust 2021 will be a great place to start at because it will represent 95% of what the language will become having already been put in place. From that point there will certainly be additions to the language in the forms of libraries and features but the mechanisms of how you write code in general will be solidified.
Until then yea, theres a lot of churn along the way to having a "mostly complete" language, especially when the point of the language is to basically be a kitchen sink of everything.
I'd be willing to bet Rust 2021 will be a great place to start at because it will represent 95% of what the language will become having already been put in place. From that point there will certainly be additions to the language in the forms of libraries and features but the mechanisms of how you write code in general will be solidified.
Until then yea, theres a lot of churn along the way to having a "mostly complete" language, especially when the point of the language is to basically be a kitchen sink of everything.