> Unfortunately, it is often used as a killer argument to chop up a software system beyond all recognition.

In all my years, all the companies and codebases I have ever seen, I have literally never seen a system chopped up this way by the SRP. The number of monoliths, though, are uncountable. The number of modules where some function is trying to juggle 8 different tasks, all conflicting … this is the constant state of affairs of actual code in the industry.

The SRP is not about chopping code up into (literal!) single lines; as I (and many others — this isn't some unique thought of mine) the SRP is about semantic, not syntactic — responsibility. It is fine, within the SRP, to have syntactically identical functions, if they serve semantically different purposes. "Are these two functions/sections of code bound to be the same by the law of physics?" If "no" … it's fine if there's a little copy paste here and there. Copy B's requirements might change down the line, and coalescing them into a single copy would be pain later down the line.

Drink with moderation.

> The big advantage of a group 0 component is that you can consume it within components from any other group (like blood type 0 (sic) can be received by any other type).

sigh. The blood type is "type O". Though, I do like the A/T separation, and yeah, generic-ish things become away of specific logic is usually a smell. (Though I'd love, like, some thoughtful reasoning. It resonates with me … but maybe a "why?".)