(if you're using Ethernet, you're tethered anyway so an adapter isn't really an issue). Heck, there were still express card slots.
Adaptors are an issue as they work loose. When you constantly plug and unplug the adaptor the port becomes worn and the adaptors have a habit of falling out. If you are left-handed you tend to snag them with your notebook. It's also a pain in the ass if you have to use an adaptor when you are plugged into some kit in a data centre squatting on the floor.