I feel like IPFS is taking an interesting approach to this. They aren't trying to rebuild modern computing from scratch, however they are designing a tool which, as the name suggests, has the ability to scale basically unbounded. I'm talking in particular about their focus on defining specs that are themselves parametrized by other specs. At the base of this is multiformats which are a suite of specs for things like network addresses which allow you to wrap any current network protocol like tcp over ip over ethernet or dns over https over quic over udp over whatever. By using these paremetrizable protocols they are lowering the marginal cost you mention and making it much easier to migrate to improved technology in the future.

It's been a while since I seriously looked into IPFS, but this is what I remember about it.