rich text content should never be the default paste. just give me the damn text I copied
I know that’s a lot more words to say a similar thing, but it avoids two problems with how you put it:
1. Not everyone will share your preference. (I’d hazard a guess that it’s a minority preference, albeit one I mostly share.)
2. It’s self-contradictory. The “damn text I copied” is not just an array of characters: it often includes formatting; it frequently interpolates other content that isn’t even text at all.
The latter is largely the basis for the former. You—and I, mostly!—might be after that array of characters. But many many people are after that richer content, and would be utterly baffled by copying something rich only to get that array of characters on the other side. And quite a lot of people would have little recourse to get what they want.
This is why the multipart clipboard solution is a pretty good compromise. It could be better! It could definitely accommodate the preference for plain text. But it can only be better for those of us with that preference, without regressing for the much more common preference, by keeping the common preference as default.
In many cases I do not particularly care whether an email is in 12pt blue Verdana or 11pt black Arial, I absolutely care about there suddenly being a big blue word in the middle of my otherwise-consistent paragraph.
So neither "rich text" nor "plain text" are really correct: often plain text is good enough, but sometimes it's easier to correct the rich text.
More generally, when editing a document I want to be able to view both formatted text and "escaped" contents (like "view source"), and when copy-pasting or saving text, I want to be able to convert formatted text into "escaped" text to diff, and also paste text without misinterpreting asterisks and angle brackets as formatting information (until I explicitly copy text as source and paste as formatted).
I use Obsidian for note taking, and discovered one very useful feature: if you paste formatted text, it removes everything except what can be handled in markdown (approximately, things corresponding to html tags, not to styles/CSS). You can then copy it back out as html and paste it and it will have exactly the right amount of formatting.