We saw an entire episode of Twilight trying to figure out Pinkie Pie and giving up on it after a lot of pain. I'm pretty sure everypony does their best to ignore Pinkie Pie's odd breaks of physics.
Really? I'll fully admit that I have no real knowledge of economics but why would choosing first give you worse sale results? Also doesn't Filthy Rich get his choice of product?
The main thing is that Applejack has no control over the jam deal, and thus she can't be judged on how bad of a deal it actually is. Not while Granny is in control who is a bad business pony.
Something everyone forgets is that Flim and Flams machine is unique to them. They need to build it, and it takes a unicorn either with a similar special talent or enough of a mastery over magic (like Twilight, and perhaps Trixie) to power it. It's not like human machines which anyone can really use and can be mass produced. Your point remains valid and I honestly think Applejack would be open to using a machine if the deal hadn't been so horrible for them. (They would have lost too much money by accepting Flim and Flam's initial deal therefore sticking to the old ways is still better. If Flim and Flam gave a better deal then I think the Apple Family would have accepted it.)
They didn't win Sweet Apple Acres they won the right to sell cider. So they couldn't just wait. I imagine they were depending on the money from the cider sale to buy Sweet Apple Acres. I suppose they could have tried to stop the Apples from selling cider but who would enforce that in Ponyville?
Now this is completely true. Granny is not very good on the whole business side of things.