First of all, "parasitic" is a very derogatory term to apply to these nations. They are no more parasitic than out of town supermarkets.
A parasite is omething that lives off a host to its detriment. It is easy for a small island nation to be parasitic off larger ones. The problem for the USA, UK, Germany etc is that there are no larger nations for them to be parasites of, nor are their native peoples to steal land from or colonies to exploit. In short someone, somewhere has to do some work.
Second, you suggest Liechenstein as a useful model for a modern industrial society that has no control over its currency, but then go on to criticise Andorra as a useful model. Why?
Actually I discounted both as models. I don't consider the ecconomy of a country of less than a million to be particularly informative in considering the ecconomies of countries of fifty or a thousand times that number for the reasons advanced above.
Third, you have missed the point I was making, that of Goodhearts law, which loosely states that "attempts by the government to regulate or tax one channel of banking business quickly lead to the same business being conducted through a different channel which is untaxed or unregulated". Surely the fact that every large nation has its banking tax havens (eg. UK has the Channel Islands, the US has the Caribbean islands) is proof of this?
I'm very skeptical about any idea that is referred to as a "law". The experience of science is that natural laws are no more constant than human ones. In the social sciences such terms tend to indicate no more than the existence of physics envy. The greatest danger is when the title "law" causes the importance of an effect to be mistaken. Just because an effect can be observed and explained does not mean that it is the only effect. To call something a "law" is almost guaranteed to lead to biased analysis. Goodhearts theorem is overbroad as stated. The banking industry will clearly attempt to move to the most beneficial channels. That does not necessarily mean unregulated. A banker's main product is trust. The fact that a bank is regulated by government increases consumer confidence and trust. If I place my money in Midland bank UK I know that those deposits are guaranteed by the government of the UK. Even if the bank itself becomes illiquid I can recover my money. The cost of this security is regulation which I am as a customer happy to take the benefit of. The fact that a proportion of money is diverted through tax havens does not imply that all money will be so diverted. The major banking centers of the world continue to be London, Geneva, New York and Tokyo, all of which are heavilly regulated. The final factor you exclude is that of ecconomic imperialism. Small countries don't have unlimited opportunities to exercise their sovereignty as the govt. of Panama discovered. While a country has the theoretical right to become a drug trafficing haven it faces the risk of sanctions ranging from ecconomic pressure to invasion and occupation. Similarly the Swiss govt no longer offers the same anonymity it once did. Phill