The thing is, you can almost always weasel your way around the borrow checker with some unsafe blocks and pointers. I tend to do so pretty regularly when prototyping. And then I'll often keep the weasel code around for longer than I should (as you do), and almost every time it causes a very subtle, hard-to-figure-out bug.
Some people say that after a while, they learn how to structure their program from the start so that these changes do not become necessary. But that is also partly giving up incremental development.
As an example, consider a pointer to a const object as a function param in C++: I can cast it away in a second and modify it as I go on my experiments.
Any thoughts on this? How much of an extra friction would you say is introduced in Rust?
The problem is Rust (and its community) does a very good job at discouraging things like that, and there are no guides on how to do so (you might get lambasted for writing one. maybe I should try)