Not really the same thing though; a quote exists as actual content in the post. When people “quote” a tweet or “retweet” a tweet they are linking to it through the built in twitter UI. Imagine if I tweeted this on twitter:
Well,
@joejust said ‘I like apples’ and I find that outrageous!
If Joe deletes his tweet that said
I like apples
There’d be no expectation that my tweet quoting him would be removed or modified.