I think the point is that coinbase is struggling to compete when there are tons of exchanges out there offering low/no fees and ludicrous interest payments on coins kept on the exchange. Even if those other 'exchanges' do all seem to be turning out to be ponzi schemes... For whatever reason people keep flocking to the next one.

I have realized that being a ponzi scheme is a feature not a bug in the crypto space. A chicken race to pull out as late as you dare.