If `Text` and `SelectableText` exist, I would call that an opt-in. The default is "Text" (not selectable) and a modifier can be applied to opt into using "SelectableText". It would be different if they were called "UnselectableText" and "SelectableText".
Seems like every dev using Flutter for more than a few days would know that both `Text` and `SelectableText` exist and pick the one that's relevant to whatever kind of text they're adding. At that point, it's the dev's fault for making a conscious decision to make text selectable or not (if they choose wrong); not really the language's.
https://api.flutter.dev/flutter/material/SelectableText-clas...