Still got it backwards on Lessor (the landowner) and Lessee (the oil company). And no, a contract is a contract and the leases from the 30's are still good. On what basis could a court rule otherwise? The law does not protect you from making a bad deal. They were probably being paid the "going rate" and on the same lease form as everybody else.
The share of production referred to in my earlier post is a landowner's royalty, or lease royalty. Not a non participating royalty interest.
I represent one landowner whose lease was signed in 1928. The Lessee was the Texas Company. The consideration was for $100 per acre (somebody figure out what that is today) for 954 acres and the royalty was 1/6th. In 1941 a like lease was let to the Texas Company (the Lessee) and provided for 3/16 royalty. Both leases are still producing today. Many wells were drilled and not once did we complain about 80+ years of production.
As for the uneducated landowner, they are his minerals and he chose to lease and enter into a contract, took money for bonus and royalty and still producing and is it fair? I guess that the heirs say no.