Avast not detecting old MS-DOS viruses! Why?

[Lisandro]

I think it's not that simple. We're not talking about disk usage, but the final engine and Avast performance: new technology that requires to extinct older ones.

[TrueIndian]

Whats the point of detecting something extinct?? When if you do run then on today's MS supported OS like Win7/Win8 those guys wouldnt run on them or they would run and then be unable to do anything and crash.

Those MS-DOS stuff are dinosaurs in the malware age.What's the point of wasting time and energy on detecting something that is not going to be alive in the real-world for not more than a day or less or which is years old like MS-DOS viruses.