No doubt multiplexing is good, better in the transport layer though not protocol.

Protocols should be programmable. Currently HTTP/2 requires libraries and being binary by nature there are more changes for vulnerable libraries, that is a fact. Due to them being more complex there is more chance for error and holes.

The smarter move would have been transport or a combination of a protocol surface and a protocol transport layer if putting it in the transport layer was undoable.

Iterations are better than the "second-system effect" in most cases. Engineers are making too many breaking changes and new standards that benefit companies over the whole of engineering and internet freedom and control. Companies largely wanted to control these protocols and layers, and they have done that, you have to see that was a big part of this.

HTTP/2 benefits cloud providers and Google (especially since they drove this with SPDY then HTTP/2 then QUIC now HTTP/3) etc more than most engineering and it was done that way on purpose. The average company was not helped by adding this complexity for little gains. The layers underneath could have been smarter and simpler, making the top layers easy is difficult, but that is the job.

In a way HTTP was hijacked into a binary protocol and should have just been Binary Hypertext Transfer Protocol (BHTTP) or something that HTTP rides on top of. Just too much transport bubbled up from transport layer into the protocol layer with HTTP/2 and a bit of a mess or leaky abstraction or a big ball of binary.

> We live in complex times and the threat models are constantly advancing. Addressing those requires protocols that by their nature end up more complex. The "simple" protocols of the past weren't designed under the same threat models.

The top most layers can still be simple even if you are evolving. Surface layers and presentation layers can be simplified and making them more complex does not lower their threat models or vulnerabilities, as we see with the OP article, vulnerabilities always will exist and when it is more complex they happen more often in engineering.

I have had to implement MIME + HTTP protocols and RFCs for other standards like EDIINT AS2 and others. Making a standalone HTTP/HTTPS/TLS capable web/app server product is now many times more complex and will be moreso when HTTP/3 comes out. Not fully yet but as time goes on consolidation happens and competition melts away by making things more complex for minimal gains. There are lots of systems that can still use HTTP servers that are embedded and other things that will be more complex now, and again for minimal gains.

Software should evolve to be simpler, and when complexity is needed, it needs to be worth it to get to another level of simplicity. Making things simple is the job and what engineers and standards or product people should do. Proprietary binary blobs is where the internet is going when you start down this path. I am looking forward to another Great Simplification that happened when the internet and early internet standards were set out, as that spread technology and knowledge. Now there is a move away from that into complexity for power + control and little benefit. We are just in that part of the wheel, cycle or wave.