Why is Apple using short code SMS for 2 step authentication?

I have been trying for months to get 2 step authentication to work on my AppleID but I never got the SMS code from Apple. In the past I have had no problems with receiving 2 step authentication codes from Google, MS or Yahoo so I knew that worked. I knew that my MVNO blocks short code SMS because they have been used to scam/charge people for services. That got me to thinking would Apple be using short code SMS to send key information for 2 step authentication? I spent hours looking through posts here and on Google and discovered a post by "yohdaddy" in this thread

Anyone having problems with 2-step verification & T-Mobile (USA)?

that indeed is what Apple is doing! Why Apple use short code SMS which providers sometimes block and will not always unblock? Use a normal 10 digit phone number like Google, MS and Yahoo does. That way critical information like 2 step authentication verification codes will not be blocked. Surely your company can afford it!