The underlying principle is...
Always try to do the most with the least
You can never judge the quality of a sound mix simply by...
Counting the number of tracks it took to produce it
The quality of a sound mix depends on...
The initial choices that were made
The quality of the sounds
How capable the blend of those sounds was of exciting emotions hidden in the hearts of the audience
The same principle applies to all the various crafts of filmmaking...
Acting
Art direction
Photography
Music
Costume
Others
Editing
The film is cut for...
Practical reasons