I don't see the business world adopting "serious" secure messengers anytime soon. People don't want to send business stuff over WhatsApp, so we'll have to "both

I don't see the business world adopting "serious" secure messengers anytime soon. People don't want to send business stuff over WhatsApp, so we'll have to "bother" with email a couple decades longer. But I really hate that I can't encrypt business communication, like invoices or contracts, without resorting to encrypted.zip. What's wrong with fixing that situation?