There was no lifetime for X3. That ended with X3e update.
The lifetime membership was offered up until about this time a year ago in 2016 and was for Platinum.
Artist, Professional and Platinum have had monthly updates more or less since the beginning.
If a person chose not to pay at the end of your years term then that's your choice and you would no longer have access to more updates. I really don't think there's much you can do as everything is done through the Cakewalk store which is now closed. You can't buy new Studebakers either.