Cryptocurrencies might be a problem in this plan, and satellite internet access itself might become a currency (since unlike cryptocurrencies, this one both has almost an intrinsic value and provides its own infrastructure that's very hard to block, where as cryptos rely on external sources of Internet access).

It also depends - drugs have consistently won the war on drugs despite being a physical product that needs a local supply chain and various anti-money-laundering and banking/finance regulations that should make it hard to fund the operation. Satellite internet access is likely to be even easier as it doesn't rely on a physical product (if we reach this stage there's going to be clandestine satellite terminals built locally, so blocking shipments of the real thing isn't going to cut it).

The only solution, apart from North Korea-levels of isolation (and even then, NK has the advantage of their population being isolated & indoctrinated since birth, something most other countries won't achieve even if they turned authoritarian overnight) would be detection followed by harsh punishment, but this has the downside of not only wasting the disclosure of detection capabilities (that are useful to the military) but also outsourcing the R&D of evading such capabilities into the open which enemies will no doubt pick up on too and use against you in a conflict.