I agree, when you go from RCA analog format to digital mpeg4 or what ever the file type is then convert it to youtube or vimeo then display it on a website, it looses a lot of quality.
Here are some examples. Exactly the same flight, just two are screen shots of vimeo and two are the original mpeg4. It looks better in the goggles though. The RCA to Mpeg degrades the quality quite a bit.
Vtx's can only transmit in 640x480 but in a few years I am sure we will have security cameras with the resolution of gopro hero and transmitters the size of thumbnails that transmits 1080 to the moon and back