More or less, although each (especially domestically) breaks it down slightly differently in terms of what you're missing when you buy basic (whether elite or kettle) and what you're getting when you buy extra legroom. DL and AA brand basic more distinctly by using "Main Cabin" as the branding for vanilla economy and only using "Economy" in "Basic Economy" (and then DL goes further: branding extra legroom in a way that makes it seem like a different cabin and in some ways treating it as a different cabin with elites needing to clear upgrades and its own boarding group).