If you think binary protocols are so great, you have to then explain why text protocols are winning all over the place. People tried to do binary for a long time before HTTP won. We had all kinds of RPC mechanism - CORBA, DCOM, etc. Even the winning data serialization formats are mostly text (JSON, XML) despite the fact we know it's less efficient. Even where people make binary versions the ones that succeed are direct one-to-one translations of the text (eg: BSON).
In the end, it is formats that people can understand that win the day. You can't just write that off as if it has no value. It plays out in technical ways: all the CORBA implementations ended up having very poor interporability partly because they were hard to debug. Nobody could actually look at a CORBA exchange and see what was wrong with it.
It's because developers need to read JSON/XML regularly. They validate the data the are sending to the client, they create test cases, the testers often read them as well, it is sometimes stored them in databases. It's because the format changes so frequently that reading it is important.
HTTP is not comparable because it never really changes. It's a fixed format. And frankly the majority of developers never need to go down to that level anyway.
HTTP is not fixed and is in fact very flexible. And even if it were fixed, that doesn't make it broken and certainly doesn't mean you get to replace it with a binary protocol. They don't compare.
I'd wager every site sitting behind CDNs or a varnish saw a developer go down to telnetting to port 80 to debug the cache behaviour. If you include frontend developers, sure your majority of developers assertion is true. Select sysops only, and you'll be e surprised.
In the end, it is formats that people can understand that win the day. You can't just write that off as if it has no value. It plays out in technical ways: all the CORBA implementations ended up having very poor interporability partly because they were hard to debug. Nobody could actually look at a CORBA exchange and see what was wrong with it.