The ports are there for a reason, it is idiotic to serve everything over http as you would need a mechanism to distinguish the different flows of traffic anyhow.
We can either have a standard and accept that bad actors will use it against us, or we can accept the chaos that results from abandoning it.
I think this is an acceptable alternative. In the same way that your mail service is legally required to deliver your mail as part of their universal service obligation (without reading it).
Reverse proxies can disambiguate based on the SNI. I could run telnetd on port 23, but have port 23 firewalled off, and have my reverse proxy listening on port 443 with TLS forward anything going to telnet.mydomain.com to telnetd. Obviously, my client would need to support that, but a client-side proxy could easily handle that just as well.
You would need to agree on a protocol and you would gain all the advantages but also the disadvantages of the tunneling protocol.
Protocol multiplexing/demultiplexing is a feature of software like sslh, nginx, and HAProxy exist, and they don't need to listen on multiple ports to speak multiple protocols or connect multiple services. Many advanced reverse proxies can do this with stream sniffing of some flavor.
People already do actually run everything through port 443 simultaneously.
If you route all your traffic through https that comes with all the upsides, for example the security layer (ssl). But also the downsides of for example overhead of headers. Currently we have an overarching (network layer) protocol, it is called IP. It divides the traffic into different ports at the host, these ports speak different protocols. If you move the multiplexing higher up the OSI stack, you are violating the principles of separation and making your stack less flexible, you are mixing OSI layers 4: transport up to 6: Presentation. Conflicting these layers can lead to big problems as this includes things like the Transport layer, for example the difference between udp/tcp is included there.
The beauty of the network stack is that there are certain layers that separate responsibility. This allows the stack to apply to wildly different scenarios. However I do agree that there should be no filtering applied on behalf of the customers.
