>Then as the country’s economy develops the need for these illegal services disappear, or quickly gets you in trouble.
This is not necessarily the case given how large the online illegal drugs market is in pretty much every developed country. Just because weed was legalised, it doesn't mean all other narcotics will be legalised in future too.
Which given the busts of Silkroad etc. and countries changing the laws allowing them to search mail making delivery more perilous, has again withdrawn to a physical hands on market.
Or do you suggest to send some stable coins when meeting the local dealer?!?!
In many countries what the economy needs to function well includes things that are illegal.