Unfortunately, this doesn't appear to be the case. They haven't been hiding that they're gearing up for a major redesign.
If so, there are a number of other intentionally lightweight virtual dom frontend frameworks. Mithril, Riot, Preact, virtual-dom all come to mind, and there are a probably a few more.
That has been shown to not hold in actual benchmarks. The real DOM is plenty fast if you do it right.
Here's Facebook's Dan Abramov (of Redux fame): "Myth: React is “faster than DOM”. Reality: it helps create maintainable applications, and is fast enough for most use cases."
tl;dr Don't blame tools but their usage
I understand the point of frontend frameworks for SPA, not so much for Reddit profile pages which are literally single, static, pages.