As @suomi say, lighting should be the very similar in both engines, because they use similar equation and they tend to the same output - achieving physical plausible light.
(renders by Sebastian Zapata, source)
In my opinion it’s not about why Corona has better results - it is a false assumption. It is question why there’s more photorealistic works in Corona than in Cycles.
With Corona it is easier to achieve photorealistic results - there’s easy and fast tonemapper, realistic bloom and glare, more built-in features (ready-made materials, thin glass, camera vertical guess, triplanar, light groups, light linking, better displacement, caustics, proxies). There’s also more community and content for that specific area which is archviz - we’ve got maxtree, more tutorials etc.
Besides that Cycles is an engine made primarily for animations and Corona for static images (mainly architectural visualizations) so the development is also different.
There was some tests to compare engines (this and this).
If somone would made for comparison the same exterior scene for Corona and Cycles with better results in Corona - then we should talk about the quality of Cycles.