Both sides are possible, depending how you interpret the question.
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Is Rust too difficult to become as broadly-used as something like Python? Probably. The majority of the code in the world doesn't need that last 10% of control and rigor that's the pay-off for the extra complexity.
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Is Rust too difficult to supplant C++ as the default choice for systems programming? I've actually argued that Rust is easier than C++, so no. Having the compiler check more things is incredibly freeing in what you can just do without needing to stress over it.