I was doing some research about many exchanges and your comment reminded of them.
Poloniex was born years before many others and thought they were fully developed and no change / improvement is needed and look where they are today.
As for working behind closed doors ... are we talking about Apple? Usually, Crypto developers announce / brag about their short / long term plan well in advance so people like me remain excited!
Ethereum 2.0 started their noise years ago!
But ... just realized I wasted your time! My response should’ve been: Source, please?