Except that he didn't say that at all and has given extremely detailed accounts of the current thinking at the time in history (they were already looking towards the upcoming limitations and bottlenecks they would face in expanding RAM sizes).
Although it is true that solar and wind are dropping in prices recently I don't think an urban legend misquote has any relevance.
In the future you might want say 'misattributed' or 'wrongly attributed' for this case.
The term 'attributed to X' can mean "is widely but wrongly attributed to X", but can also mean "I heard it somewhere and it sounds true so I'll go with my gut feeling instead of verifying it" or "I hear there are doubts, so while I have no opinion, I'll keep my bases covered."
Personally, rather than be stuck in that mire, I would suggest quoting Prof. Frink from Simpsons:
> 'I predict that within 100 years, computers will be twice as powerful, 10000 times larger, and so expensive that only the five richest kings of Europe will own them.'
This in turn came from the quote widely but wrongly attributed to Thomas J. Watson of IBM:
> 'I think there is a world market for maybe five computers'
> Often dated to 1943. Thorough research of Watson's writings and statements have produced no example of him saying this. It appears to be a corruption of a remark by Howard Aiken that four or five computers could meet all of the United Kingdom's computing needs. See Ralph Keyes (2006), The Quote Verifier.
Of these, only the Frink version has an accurate attribution. I think the other two come with some malice. By repeating the urban legend as if it's relevant, I think you are forwarding that malice, even if unintentionally.
They can drop to zero, they are still not going to replace regular power plants because you can't guarantee baseline power with them. You could drop all power generated with them into pumping water to huge reservoirs, so they can generate baseline power around the clock, but it's not feasible in a lot of places, and you are losing a lot of energy just to move the water up and down.
Not sure whether you're just using the term incorrectly, but I see this claim repeated a lot so forgive me for explaining: you do not need baseline power.
Baseline power is the observation that if we have less than ideal power plants that need to run 24/7 to be economical (usually because of high capital costs, e.g. nuclear plants), we can still deploy them if we then also invest in other plants for filling in the peaks.
See, the important part here is that you always need to meet demand (maybe you can shift demand around a bit, but after shifting it the observation still holds).
If you have baseline plants, your supply curve is a flat line so the peaks in the demand are the holes you need to fill in somehow.
With a renewable source like wind or solar, you may actually be able to meet the peak demand, but then have a hole in the supply at some other point (say at night, or when there's no wind). So you need to fill in these somehow (as you say).
Although it is true that solar and wind are dropping in prices recently I don't think an urban legend misquote has any relevance.