Sure, It may be possible “IF” cold fusion is ever brought to the same functional safe reliable and inexpensive status as your existing power supplier.
Yes. Obviously, if cold fusion is not perfected, this will not happen. That goes without saying. Meaning, it is so obvious, and everyone here knows it so well, you didn't even need to say it. Why bother? Do you think I am unaware of the technical challenges that prevent the use of cold fusion today? Do you imagine you are telling the audience here something it does not know?
If cold fusion can be controlled it is likely to be about 10 times cheaper than any other source of energy, and ultimately thousands of times cheaper. See:
The idea has merit, but once costs and application engineering expertise are brought into the discussion, dc power for commercial/industrial uses dies a quick death.
Spoken like a person stuck in the eternal present. You should realize that conditions change; technology changes, and that which would die a quick death in one era -- and that which is flat out impossible -- is commercially unstoppable in the next. See, for example, electricity, automobiles, air transport, computers and the internet.
You have to understand, Clarke was talking about the future, not the present. He thought a lot about the future, as do I. See:
(He thought about the past, as well, as you see from the photo of his pet Tyrannosaurus rex.)