Gmail doesn't distinguish the replies either, except by the "barelyGmail where?
As my screen shot showed, the Gmail app on my Android phone makes them distinct with three different markings: color, indent, and ruling line on the left.
Gmail on the web (Firefox on a Windows desktop) not so much: it indents a fair distance (visually looks like a tab stop) but no color or line.
I wonder if different settings or themes in the web version of Gmail might affect how blockquotes are displayed. I wouldn't think so, but it may be possible.