To answer the original poster's actual question:
I think you should evaluate each therapist and social skills program individually. Sure, most may be lame, but some may not be. Also keep in mind that you are NOT an expert at training for these things. What appears to be a waste of time may actually be getting to the root of a problem that you haven't even noticed.
As someone who is recently self-diagnosed, but who never received any kind of help, I can tell you what I would have appreciated:
Parents and adults who did not respond to my problems with platitudes like: "If you just be yourself, people will like you." Listen to your child and help them work through specific instances of things that have made them uncomfortable. Offer concrete suggestions based on how the real world works in their school. Ask for feedback as to how that advice is helping.
Provide lots of opportunities for success. I am talking about social success here, not just success in completing tasks. Play dates may be good, but I would suggest that you get your kid into clubs based on activities they like, but that have a large social component. For instance, If your kid likes trains. Don't just take them to a club where someone shows off their latest train set. Take them to events where the kids get together over pizza and talk about their trains in a less formal manner. Perhaps have them build trains together, then all get together for the pizza party. You should perhaps direct the activities (as in plan for all the kids to have stuff ready to build said trains) and monitor for bullying and bad behavior, but then let the kids take it from there. Learn the subtle signs that indicate that either your kid is uncomfortable or that other kids are perplexed by his/her behavior. Now, watch for those signs during the activity BUT DON'T INTERRUPT DURING THE ACTIVITY. Now, the next day, pick a few things to talk to your kid about. Always make sure to let your child know that they aren't "in trouble" for "acting wrong" but that you just want to help them understand how other people think. Make it clear that this is the kind of discussion that ALL good parents should be having with their kids, rather than it being some kind of remedial activity because they are broken.
Avoid bullies like the plague. While it is OK for other kids to be perplexed or confused by your child's behavior, if they actually start picking on your kid then take steps to get that bad apple out of the club, find a different club, or talk to the other parents and fork your own club, without the bullies allowed. The longer bullying is allowed to persist, the more socially isolated your child will become. It is almost an exponential scale.
I know someone who is much further along on the autism spectrum than I am. However, when he was around 14 or 15 his few friends got together and decided they were going to teach him how to be less socially awkward. After each interaction they critiqued him, much like members at a ToastMasters meeting critiquing a member's speech or presentation. Now, though he still has many autistic tics, he is far more socially skilled and successful than I am. To my ear, he always sounds so phoney and patronizing, but everyone seems to love him. He meets and flirts with new women with ease and does very well at work, garnering the praise of many of the managers. Mostly because he has learned when to keep his mouth shut and exactly when and how to make suggestions.
Finally, keep in mind, this will be a lifetime project. Never think you are done. Life will always present new things that will always be difficult for your child, well past their mid-life crisis. The most important thing you can do is be that sounding board that they can always go to for advice.