🚀 go-pugleaf

I would think that this would create the sort of slow non-performing
ISO implementation that gives new protocol implementations a bad name.

There was once an implmentation of TCP/IP for V6 UNIX on a PDP-11/45
that was provided by BBN, that was architected in a way reminiscent of
what you describe.  On a 1 Mbps token ring LAN, the Telnet protocol
implementation ran at 300 baud with 100% CPU utilization.

I know of commerical products that have used architectures like this,
and have been reviled for their atrocious performance.

I would strongly recommend reading RFC 817: Clark, D.D., "Modularity
and efficiency in protocol implementation", July 1982.  While it is
about the IP protocol suite, it is every bit as appropriate to
avoiding ISO implementations that are strangled by their own Computer
Science elegance.