It is a solved problem. Here is a solution that requires something of the order of 1,000,000th of the resources of your proposed idea, no subscription, and runs so fast that you would not even notice it on a machine from 20 years ago:

    > grep text/html ~/.mailcap
    text/html; lynx -width 72 -assume_charset=%{charset} -display_charset=utf-8 -dump %s | sed 's|^   ||'; nametemplate=%s.html; copiousoutput

If you want something more modern:

    text/html; webdump -dli < %s | sed 's/^  //g'; needsterminal; copiousoutput