Lenses can have better color rendition than other lenses beyond what can be corrected for in post; sensors can have better color rendition than other sensors beyond what can be corrected for in post. Whether the people posting these comments are right or not, in theory their ideas are sound.
Sensors can have stronger or weaker (or more or less IR sensitive) filters in front of their photo sites. The more frequencies the color filter rejects (the deeper it's tinted), the more vibrant the colors the camera can reproduce--and the less sensitive the camera is to light. DXOmark's "portrait" rating measures for this exactly (in theory).
Lenses can be more or less corrected for aberrations, and not just garden variety CA; apochromatic and superachromatic lenses should have dramatically reduced longitudinal chromatic aberration (any lens with ED glass or ULD glass or fluorite should have LoCAs substantially mitigated) and that means as the image goes out of focus its out of focus areas take on magenta/green tints. A properly corrected lens will not have this! And that means everything, in focus or otherwise, should be almost perfect in terms of color, and areas that are just out of focus but still smaller than the circle of confusion look better, too...so really everything looks great.
I used to shoot Fuji 4x5 and 120 Velvia. I stopped shooting film a year or so ago and miss it tremendously. Velvia has color rendering that, however inaccurate, looks like nothing else. If you look at Velvia's sensitivity curves they're incredibly narrow and reject most light. And so photos taken with Velvia have amazing saturation and vibrance. Just the richest, most outrageously deep colors (and contrast; it had extraordinary d-max). I also shot with a set of apo-sironar-s, with ED glass, and the lenses and the IQ is intense. Here's an image shot on 4x5 velvia with such a lens:4x5
Can your dSLR produce colors like that? I doubt it.
But it can get close. Optically, better. The Coastal Optics 60mm f4 is corrected for visible and IR/UV light and produces the most beautiful colors, better corrected than any other lens I know of. I've seen images taken with it and a Nikon D3 that have amazing color, noticeably better than most even in web size.Coastal Optics