I think we will see adult pull-ups someday, though I think it’ll be a long time. ABDL companies will purchase their own diaper machines first, and even that isn’t close by. Then there is the design hurdle.
Casey is working on it. The issue is, he'd actually need a very specific machine to make them, and, as of right now, such a machine doesn't exist for adults. Rest assured, he is working on it. Until then, Northshore GoSupreme, Abena Abri-San, or similar, and either temporary tattoos, or, a Sharpie, and you can make your own.