I don't understand this comment. The new M1s all have 16GB of RAM integrated with the SoC, and it can't be upgraded. If you had 32GB on your old machine and didn't need that much, that's kind of on you, right?
The M1s have 8 GB standard, 16 GB is a $200 upgrade. The parent is stating that 8 GB is actually fine and that people will be paying to upgrade to 16 GB unnecessarily.
Modern OSes and apps make aggressive opportunistic use of available memory for caching and other performance-enhancing purposes. A side effect of this is that however much RAM you put in your machine (within reasonable limits), it always looks as though you're using the majority of it once you're running a few apps. Hence the large number of people who think that they "need" 16GB of RAM when in fact they are just getting a small to medium performance boost from it.
You can see a concrete example of this here: https://www.youtube.com/watch?v=PP1_4wek4nI The 16GB Macbook Pro is "using" more memory than the 8GB model to run the exact same tasks.
