“Dead artist don't need the money”. Certainly there is work to be had and it may increase in value. Sometimes the value is strictly regional. The work of a regionally famous person from North Dakota may not have great value in New Jersey, but then it all depends on who might be looking for such a piece. Just like people, art travels everywhere. And so the work of a north east artist may end up in Texas or London or anywhere. And someone in Canada may be looking for specific work. A lot of attics hold fabulous work. The internet is a wonderful tool to find art and art values, but there is no guarantee the information is available even for very fine artists. Rule of thumb, always buy what you like. Research provenance and value as much as possible. And even be willing to buy work with no signature. There are many pieces in museums that hold no signature and are not even artist attributed. But the work is outstanding and museum quality. Learn to recognize quality, style, outsider art, again medium. Without signature or provenance, the price and value is going to be less.
"Art washes away from the soul the dust of everyday life".