As Chinese Evernote (yinxiangbiji) team has already implemented markdown support in their version of Evernote, I don't see why not.
I suppose you don't see much requests here because all people using markdown were already switched to new platforms.
People abandon or do not use Evernote for a reason, as generation moves on, Evernote itself is dying fast. If you continue to ignore any voice outside of your current user group, you will lose your current users eventually.