The reason why it's not done as much for ordinary businesses is that you can't just force someone to surrender $320M worth of stocks, real estate or wire transfers and actually keep that, it's reversible and traceable so most of it will be reversed and the rest traced. At best you can expect briefcases of cash ransom which is physically limited to much smaller amounts (e.g. it's simply impossible for a person to carry $320M in cash or fit it in a random car) and still needs laundering, and as the payoff is less lucrative then it's not worth the risk compared to other activities like trafficking drugs. Crypto, on the other hand, has this possibility to just force a large transaction and actually get away with it - so I'm just wondering why we aren't seeing cases of violently forced crypto transfers; perhaps they're just kept under wraps.