Usually no. A RAW file contains the original sensor data, while a JPEG is a processed, compressed version with information discarded. In principle, anything the camera does to make its JPEG can be matched or exceeded later from the RAW, especially since desktop software is not limited by in-camera speed constraints.

When an in-camera JPEG looks better, it is typically because of one of these reasons:

• the RAW conversion was not optimized well
• the converter’s demosaicing/color rendering is weaker than the camera maker’s own processing
• the photographer prefers the camera’s built-in contrast, color, sharpening, or noise reduction

So the advantage is usually in the processing pipeline, not in JPEG as a format having more image information.

JPEG still has practical benefits: smaller files, faster write/transfer/browsing, broader compatibility, and pleasing out-of-camera rendering if you do not plan to edit much. But for maximum image quality potential and editing latitude, RAW remains the better source.