Hmmm, wonder if this will carry over to their postpaid plans as well. Going to throttled "unlimited" service across the board would be a major change for AT&T, since it basically does away with overage charges (or on GoPhone plans, requiring customers to purchase a bloc of data when they go over their monthly cap).
I used an AT&T GoPhone plan for years before switching to T-Mobile when I bought my first iPhone. Their stingy data allotments and ridiculously high prices for additional data blocs at that time gave me plenty of reason to change carriers.
Things are a lot more competitive now, and if AT&T now offers 2.5 GB 4G/LTE and unlimited throttled data for $60/month, that cuts very close to T-Mobile's $60/month plan that offers 3 GB of 4G/LTE data on a less extensive network. Since I don't use a lot of voice minutes, T-Mobile's $30 prepaid plan with 5 GB 4G/:TE data and 100 voice minutes still works great for me, and I've yet to see anything comparable from competitors.