Don't forget to add a few billion dollars saved because of how easy it is to debug HTML. How easy to is for people to start. You press ctrl+u and see the source. There were not many platforms where you could just view the underlying instructions... when I grew up, some 8 bit machines had cartridges to hack but let's face it 6502 or Z80 assembly is nowhere near as friendly as HTML.
ctrl+u could just make the displayed representation as easy to read. There are many binary protocols/formats that are a breeze to work with if you have the right tooling. You never see the 0xa 0x8 0xf. Your tools will either show you what the bytes represent or that there was a parsing error. Those parsing errors would be rare in the average case, just like debugging strange unicode issues in HTML today.
At that point, how big is the win in a binary protocol versus compression? Wouldn't a binary version be just a mapping between the HTML tags and a bit representation which a Huffman compression directory can just recreate on the fly but better?
There are a fair amount of benchmarks out there showing the difference in compressed JSON vs things like protobuf, msgpack, cbor for HTTP APIs. It's a decent stand in for this so you can get you a general idea of the scale.
It's also something you can easily build and test for yourself today. The compression ratio for that test is really depends on the content of the JSON, but that will be the same for some theoretical binary HTML too. From my real world experience, I saw msgpack coming out slightly ahead of compressed JSON with a non-negligible CPU advantage too.
This differences really are extremely minor. But when the tooling is designed well and easy to use then these minor performance wins are free. It is something you never notice or have to deal with directly.
My argument has not been well made -- nor was effort made to understand it -- but the textual nature of HTML extends much further than seeing it, it's also editing HTML with whatever you want. You can slap together a webpage with Notepad.
