It's obvious that bitcoin is a ponzi.
Ponzi still exist nowadays because of bitcoin, so it means that bitcoin is not a ponzi. There's a lot of new platforms spreading all over the social media that uses cryptocurrency just to attract many users in their ponzi platform. A ponzi is a pyramiding scheme, a business platform where the money you earned is from the other people who put initial investments. There's no referral bonus gained to those who recommends bitcoin to the other people. And there's no specific amount needed for you to invest in bitcoin, even a 10$ can make you money but don't expect too much.
I think you tried to say that 'It's obvious that bitcoin is not a ponzi '. The headline in your post is misleading

maybe typo.
Actually there are millions of ponzi scheme all over the globe and the new adopters in the ponzi scheme always gets some benefits. When the bitcoin value become the hot topic in the market then all the other people who have lost their money into some Ponzi scheme though that its a similar type of scheme, without knowing the actual fact about the bitcoin. Nowdays people are well aware that bitcoin is not a scene at all.