1) they either have ways, which would be incredibly valuable and worth keeping secret

or

2) there isn't a way or its not worthwhile; just use Monero instead, dawg.

"why hasn't anyone made, like, a secure Telnet?" because they created SSH and VPNs, same idea.

HN is pretty strongly focused along a particular dev culture that has at best a deep distrust of and at worst disdain for finance. I appreciate that, as a long time poster, you're posting this but I personally have given up that HN will ever become anything more than r/hackerculture.