You're right about disk space. Recently I moved over to a NAS, and had about 1 TB of files; mostly pictures and videos I had taken over the years (concentrated in two epic overseas trips). I can see already that that's going to grow, a lot! --since I just took a short trip somewhere and managed to eat up 40 GB just taking pictures at a zoo.Disk space is ridiculously cheap these days.....
IMHO, not that much of an argument any more...and if it is, you can always choose to shoot in a lower resolution which generates smaller file sizes....
But...It's not a matter of disk space, not when someone is talking about RAM--and the person you replied to, was. It's when a picture is loaded into "current" memory and the person is doing things to it in their editor. RAM has to be big enough to hold the picture, otherwise parts of it are having to be swapped in and out of a disk. Even if it's an SSD that will slow things down.
(The distinction between RAM and disk space is often lost these days, both are technically "memory," but RAM is short term, and goes away when the computer is shut down, and disk space is long term. When a computer is actually processing a picture or video, it wants to do so in RAM but will do so on the disk--much, much, slower--if it must. And even "disk" comes in two flavors--SSD (faster but more expensive) and actual hard drives (slower but much cheaper) so there's now actually three tiers of "memory" now.)
However, even a "small" amount of RAM by today's standards should suffice for a picture (all bets are off if you're doing focus stacking or averaging 30 shots of the moon together, though---that's multiple pictures). It's really video that chews up huge amounts of memory.
I apologize to anyone who actually knew all of this before I tried to explain it.