This is totally wrong, and it is your own misinterpretation, and you are welcome to quote the exact word they used. I'm pretty sure what they mean is that with todays technology to be able to brute force against 256bit you'll need a computer of a size bigger than the universe (which is to say yet again Impossible!)
I can understand your point. A few centuries ago things seemed to be so far away like today breaking a 256 bit key. Although it is funny to watch a documentary from 1970 "how will the year 2000 look like?". No, we are not flying with cars around and no, we have no 15h weeks
I am on your side, that we never know what the future brings. But the statement from "Bruce" has nothing to do with "today's technology". He just makes the assumption that you need energy to represent information. To turn around a bit. Without that you cannot count or calculate. You need energy. And in our solar system we have a limited amount of energy (to a given time). So when you use all the energy of the solar system over its whole life span, you still have not enough energy to count to 2^256.
This has nothing to do with today's technology. Again: The statement is about energy, which you need for counting and energy is limited.