This is not an example of nor even an attempt at long horizon thinking. Voyager wasn't built with the intention that it would last for decades. It was a rush job to take advantage of a very rare planetary alignment and it's primary mission was completed 12 years after it started.

It is a testament to the ingenuity of the engineers who have worked and are still working on the project that they've managed to keep it to some degree functioning for so much longer than it was intended to last.