Good grief, my DD1 is six, and she still occasionally drinks from a sippy-- maybe once or twice a month or so-- and my DD2 and DS are nearly four, and have milk from one every night. They can drink out of regular cups just fine-- they do at the table, and during the day. But all three of them still take some comfort in curling up on my lap for some sucking time. I had to wean them too early, because I have a serious illness, and the sippy became their main source of substitute sucking. There are plenty of kids still nursing at 4, and a few still nursing at six, so I see nothing wrong with this. They don't drink juice, though-- they drink water, milk, or herbal teas.
I think it's nonsense to say a toddler is too old for a sippy. I would say that six is probably too old, but I still don't see why some people make it into such a big moral issue. And I don't mean anybody on here, specifically-- I wouldn't be snarky like that. I'm just saying in general, I don't see why it's such a big deal. It's not like they're sucking on the cup all darn day.