Respectfully I disagree. I believe what Dijkstra is getting at is that the specifics of modern computers aren’t “relevant” at all. Ultimately it’s the science of information and whats computable. Be that a modern day silicon processor at X gigahertz, a pen and paper, or a universe sized computer, that’s irrelevant for the science itself.
We don’t actually disagree. Note that Dijkstra did not say “modern computer.” He said “computer.” Computer science is in a major way about what “is computable.”