Define a pro user? Lots of professional users can get by just fine with an internet connection. The ports to a lot of people are a waste of space.
Considering we are in 2016 and Apple has always been keen to adopt new standards, I'm happy with 4 USB-C ports and the headphone jack. Losing the SD card slot is annoying as it's handy for convenience, but for me personally I only use it about a dozen times a year. An adapter to give me extra functionality (SD slot, full size USB etc) is acceptable, but only if its included in the box! As USB-C is still in it's infancy, I think it would be outrageous for Apple to charge $79 or whatever for something that should be included as standard.
Asus are bundling an adapter with their new ZenBook 3, so there's no reason why Apple can't do the same.
Why should I and the rest of us who don't need an adapter have to pay for it to be bundled into the package?
Why produce an SD slot reader for every laptop sold when only a small number will want one?
It makes no economic, nor sustainable sense...if YOU need it, then YOU buy it.
I wouldn't expect you to fork out for my USBC to Firewire adapter i will need for my audio interface...