I’ve handwritten and edited quotes numerous times. For example, when writing down a quote that is in printed material, embedded in an image or heard in spoken audio.
Agreed that we cannot make the assumption that the writer is using a specific editor. If the writer is quoting large blocks of text, perhaps they are an advanced user and likely to be using a more sophisticated editor? It would be good to see some use cases for long quotes. From my experience in academia it was generally frowned upon to quote more than a few paragraphs at a time; long quotes are at the expense of original content (perhaps @jgm would like to weigh in here).
With line blocks for song lyrics I can see a potential issue for marking up lengthy multi-paragraph songs.
If it is decided that a block syntax is necessary, perhaps we could use the same marker for familiarity, similar to how fenced code blocks use the same backtick as inline code:
>>>
This is a blockquote
Covering three paragraphs
Final paragraph
>>>
This could be an alternative to:
> This is a blockquote
>
> Covering three paragraphs
>
> Final paragraph
And for line blocks:
|||
This is a line block
Covering three paragraphs
Final paragraph
|||
This could be an alternative to:
| This is a blockquote
|
| Covering three paragraphs
|
| Final paragraph
I’m not entirely convinced of the need for this but it’s worth looking at options.