First, thank you all for the thoughtful replies. It's so helpful and reassuring to get other parents' perspectives.
If you haven't already, you should read Heidi's post here. It sums up so eloquently everything I've felt about therapy since Finn was an infant. And these feelings were really the impetus in my finally taking a long, hard look at things and deciding to reduce services. I want our life to feel like our own. I want my child to feel like my own (and not belonging to the system). I don't want the guilt that seems to go along with therapy (we're never doing enough to optimize Finn, it feels like). I've often thought that if we did away with therapy altogether and pulled him completely out of the system and had no "performance evaluations" (which is what they feel like), our life would be so great, and we'd have nobody telling us how poorly Finn is doing compared to typical children. Finn would just be Finn.
But I don't feel sure enough of myself to go it completely alone, so we've compromised by reducing therapy rather than doing away with it altogether.
Deborah, I appreciated you response so much. That's what it all boils down to, isn't it: you can push a child and push a child, but if they're not ready to ___________ (fill in the blank), it's just not going to happen. And I know that there are plenty of children with Ds who have received tons of therapy and still don't walk until the age of 2 or even later - and there are children who receive very little therapy who walk before their second birthdays. It's all a crapshoot, and I don't believe you can force it. And honestly, I don't even see the benefit of forcing it - so what if Finn were to walk at 18 months as opposed to 28 months? How would that make his life better?
As for the play things: we have a jumperoo that Finn has used since he was about 6 or 7 months old. He enjoys it. Eun had encouraged us to stop using it a while back, though, because she said that it encourages him to bear weight on his tippy-toes rather than flat-footed. So for the last month or two, I've rarely put him in it. But I do wonder if it was actually helping to strengthen his leg muscles and to feel comfortable bearing weight on his legs. We don't have a doorway jumper (as Esther suggested) because none of our interior doorways have the lip to hang it on (we live in an old house!). I still don't know what to do about getting a walker. Should I or shouldn't I? I'm starting to think that I could talk to 10 different therapists about these things and get 10 different recommendations. It just makes it all so muddy and confusing. As for a play table and a push-type walker, we have those, and thus far they haven't motivated Finn to stand. He used to stand at his play table, but he just won't do it anymore.
And the thing is, I know that Eun's earlier prediction that Finn would be walking by 16 - 18 months was hugely optimistic and probably unrealistic. And I never tied my expectations to that prediction. Somewhere in my head, I've kind of assumed all along that he probably won't walk until he's 2ish. Maybe later. And really, I'm okay with that. To me, when I take away the therapy element and the evaluation element and the IFSP element, it doesn't feel to me like there is anything wrong with Finn. Finn is just Finn. It feels like he is staying a baby longer than my other kids did. And I am really, really okay with that. I mean, don't we mothers pine for our kids' babyhoods? Don't we lament how quickly it flies by? I have a gift: a baby who will stay a baby a little bit longer.