While these systems shouldn't have these length limits, a 25-character pure alphanumeric random password already has nearly 149 bits of entropy, which might be

While these systems shouldn't have these length limits, a 25-character pure alphanumeric random password already has nearly 149 bits of entropy, which might be stronger than other cryptographic primitives that are use in these systems, if you trust that there are no effective attacks against your RNG. Brute force against such a password may already not be the easiest way to attack the systems that use it.