I find it weird that someone would just randomly stop feeding their snake. They're hard to keep at the best of times depending on the species. so if it survived years it would have been cared for.
It is very possible that the snake refused to eat or had some other condition that prevented it from eating -- when that happens, there's almost nothing a keeper can do to feed it. My last snake from my early 20s did the exact same thing for no apparent reason, and despite trips to the vet and literally spending hours each day with every feed possible, it perished.
They can survive months without eating so for it to just up and die from missing a feed is unusual. Sounds like something else was a contributing factor.