Little success in relation to years in the league.
1 cup since expansion.
Define success.
Its not only winning the Cup.
The Rangers are one of the most successful franchises in north american hockey. They have been in existence for 86 years. Never faced bankruptcy, never faced relocation. Survived World War 2, Vietnam and Korea (World War 2 claimed several clubs). Survived depressions. Survived expasions, contractions, lockouts, monopilizing (Canadiens).
They've survived and have been one of the main financial reasons the NHL has survived as long as it has.
Expecting a championship several times per decade is unreasonable. And yet, they have been to a championship nearly every decade of their existence (save 60s, 80s, 00s).
"One Cup in 70 years" is unfortunate. It's also unfortunate if that's how one discerns success.
Tell me this, how is it the Devils won three since 95 and are bankrupt. How have the Penguins won three since 91 and faced bankruptcy and relocation twice in that span.
The Islanders have won four. They won't have an arena in a couple of years. Their town practically voted AGAINST keeping them around.
Championships come and go. Be greateful for the ones you see.
Lesser clubs form and fold. The better clubs survive. The successful clubs last 86+ years.