All three have the same underlying idea: do this for every thing of that. In the first case, it's implement a trait for a type. In the second case, it's "for all choices of the lifetime" and for a for loop, it's do something for each element of a collection.
I understand how that seems logical in isolation but it's just not how syntax is usually read by people. It's done so as part of a reading context instead of as separate syntatical tokens. The underlying idea is not the same for the reader because the context is vastly different.
Rust tends to prefer reusing keywords (in unambiguously different contexts) rather than introducing new ones, because adding a new keyword is a backwards compatibility break that requires a new language edition and creates migration pain for anyone who had an identifier with the same name as the new keyword.
`impl T for for<'a> fn(&'a u8) {}`
The `for` word here is used in two different meanings, both different from each other and from the third and more usual `for` loop.
Rust just has very weird syntax decisions. All understandable in isolation but when put altogether it does yield a hard to read language.