You are asking too much from the bollywood industry (or who ever is at the helm). Mind you their movies do earn 500 to 1000 crore per movie. But it is not to preserve the heritage, on foundation of which they stand.
There are some yash raj movies compilation songs remastered by professionals. And some attempt by pros in special albums. You will have to search for them in audio cd album cover notes. CDs have become expensive.
HMV, RPG or Saregama have messed up things and song quality varies even for same songs. Personaly i find 80s/90s Tips and Venus cds audio quality very good if not the best.
Download /purchase songs from their websites (mostly mp3) to get the idea. You may sometimes be lucky.
Regards.
