> if you're founding a tech company now, you're pretty dumb to use C++
All us unreal engine using indie developers must be pretty dumb then. It’s true that programming in c# in unity is easier, but the end result of the c++ is a prettier game with more things happening at once at a higher frame rate. More grass, more characters, more animations, more AI nuance, more physics interactions, lower system requirements during a gpu shortage, etc
try rust.
The reason you haven't seen this in the global cryptocurrency industry is because of network effects and adoption curves. Most programmers would probably agree that C++ is archaic and that the software industry has moved on to newer languages like Rust, Go, Kotlin, ES6, etc. Why then do Microsoft, Amazon, Apple, Google, etc. all rely on large quantities of C++ code? Because they were founded in the last millennia, when C++ was basically the only alternative for what they were trying to do, and have deeply enmeshed ecosystems and value chains that are all dependent on their existing C++ codebase. Throw it out and you throw out the $5T+ in value they've built. They couldn't have built that up without the 20 year head start they have, but if you're founding a tech company now, you're pretty dumb to use C++.
Similarly, Bitcoin has built a whole ecosystem of miners, speculators, traders, exchanges, payment systems, wallets, etc. Throw proof-of-work out and you throw all that out, and along with it your advantage over Ethereum, Cardano, Stellar, etc.