I think you need to quantify
a lot, as in "a lot of pros need ethernet". I work in a university and I see a
lot of laptops and I don't think I've ever seen anyone plug in the ethernet except for very specific situations like LAN parties or DC++ (since people are charged per GB for wireless data over a certain monthly cap). I also work in the entrepreneurial business environment and most people have MBA, netbooks, iPads and other similar devices. It would be interesting to have other technicians opinions on this though.
In the case of the hotel room, yes that is sometimes the case... then again, I guess that is what the adaptors are for. It is the same reason that laptops no longer have 56k modems built in - it simply isn't that common these days. Ethernet on laptops isn't that useful anymore. Wireless is the default.
The challenge in any technology is to balance the realities of the world with the vision for the future. This laptop is clearly designed with the future in mind.