To me one of the most appealing things about the Macbook is precisely that it DOESN'T have all of those ports, yet the port it does have is capable enough of routing everything I would ever need over a single cable. That is elegant in a way that computers rarely are.
What that means is that for the 95-99% of the time that I will use the computer without needing any accessories, I get the benefit of interacting with a device that is thinner, lighter, with a smaller footprint. For the rare times that I need additional connectivity, once the accessory market has had time to develop (which is precisely the point of this thread, to watch that development), I'll have my choice of accessories to fit my needs. Most likely it will be a single hub with a couple of usb-a ports, a couple of usb-c ports, an hdmi or displayport, and an ethernet port. A well designed one of these will be smaller than the AppleTV or Airport Express you suggest I carry instead. If I want the convenience of a power workspace at home or the office, I can set up a larger hub like the Hydradock, connected to a monitor, keyboard, mouse, etc. and have a full-featured workstation with the mating of a single connector. Again, way more elegant than what is currently the common Mac method of individual connections to power, ethernet, video, usb cables, etc.
Your snarky comment about 'telling the client to buy an Airport Express' makes it all too clear that you've not had much experience in the real world. I do, in fact, often travel with an Airport Express as a backup option when I suspect there might be a need and the added bulk is worth lugging along. However it is by no means a guarantee that the client's network will be configured in such a way that it will work, or they may well not allow you to connect such a device to their network at all. I'll make sure to tell them your solution next time I find myself on a project site in central Africa with an Ethernet only connection, however.