I sincerely hope you are wrong. At this point, quite frankly, it could go either way. It is, therefore, completely understandable and even not unexpected that there are skepticism developed within some people not just of the ability of the El Salvador government and its leadership to deliver but also of the real motives behind all this.
Its as obvious as it can get. Every country that provide safe haven in form of taxes, security and other stuff are meant to grab cash from people that might want to visit or stay in their country. The offer needs to be as lucrative as it can get so people wont hesitate to move in but whatever it is, bitcoin gets a free worldwide hype thanks to that so yeah it works out good for both
To be fair, I don't think this is the kind of tax haven that is being offered in countries like Panama, Switzerland, Virgin Islands, Luxembourg, and others. So if you are referring to these places, I don't agree with you. I haven't seen the details of this Bitcoin City but I suppose it is not built for the rich foreigners from other countries to shirk tax responsibilities in their home countries. This is Bitcoin City so I assume that this does not offer all those kinds of offshore banking services and products which tax haven countries are famous for.
On the contrary, it is my impression that there is indeed financial independence in a Bitcoin City or a Bitcoin country. Right now, solid Bitcoin advocates and supporters are flocking to El Salvador because of what they could offer. But I don't think decentralization is reduced in the process. It is always understandable that Bitcoin supporters would be attracted by Bitcoin-friendly places.