IMO rewriting happens mostly because going to lower-level of the needed proficiency/understanding - once the product why-what-how is more-or-less discovered, its code can be commoditized and hardened, kind-a. Dynamic stuff is very powerful == becomes too powerful (and "magic").
There is quite some wishful thinking around what so-called static-typing (which is actually static type-hinting) in dynamic languages, hoping and believing that declaring something Float, guarantees it being Float at runtime.. which is nonsense. In Ada, and few other runtime type-and-range-etc-checking languages - yes. But in plain ones.. nope. C++, Java, whatever - noone checks things at runtime. Most of those do not have a way to know what some n-bytes represent, hoping it matches the expected layout (i.e. type). While, say, python very well knows what each and every object is. If asked.
Of course, one can build such real-runtime checkers, and apply them where/when it is needed and makes sense - instead of blanket policy everywhere, but noone bothers. (Funny thing is, when i made one such library 15y ago, i was spit at and told to go code in java. And, even i haven't since then stumbled on pressing need to use it myself. Having 10 asserts (or constraint checks) in some 10kLoc does not justify whole library)
That said, i think something like language-verticals might be useful. And/Or gradual hardening, on piece-meal basis. At least a standartized way for going up/down or stricter/relaxed, from wherever one is.