Ethernet, firewire, display-port, etc are all connectivity for a by-gone era; USB-A/B are gradually being eliminated from most of the industry as well. I literally have not used any of the first three in a few years, and USB probably only to charge some other device. Each to his/her own, but it just isn't needed by vast majority of the population any more. I can see a rMB with zero ports pretty soon, when wireless charging matures enough to charge with very high reliability and efficiency.
I think you're leaning a little too far forward here. While your personal use is reflected here, my own and my observation of plenty of other computer users at work and home says otherwise. Ethernet and USB-A at least will be with us for quite a while longer, because not everyone wants to be on wireless for speed, security, or reliability reasons. USB-A will be with us for a very long time, simply because there are billions of USB-A devices out there that will remain very usable for year into the future. Simple example: my full size Apple keyboard.
What's your definition of "pretty soon"? I'd be willing to bet a sizable chunk of change that we will not see a "port-less" computer for at least 5 years. iPhone will be first, but wireless charging will have to be perfected and it's not there yet. Followed by iPad, and then laptops.