The ATP store is currently back to carrying pins.
We may do more runs of shirts in 2019 if inspiration strikes us. We will definitely do our annual WWDC run in the late spring of 2020.
We still have some pins in stock. The pins now come with a locking pin back, which should help keep them more securely fastened. (If you want to add a locking pin back to your existing pins, ATP or otherwise, you can find them sold separately at Amazon and elsewhere.)