Carpet cleaning is really hard. Speaking as someone in charge of making 3K sf of carpet look like new, with a seriously small budget, rented several high dollar machines, been disappointed in several cases. Luckily I installed carpet squares and bought several extras, we just replace anything with spills. Lots of stuff just doesn't come out, there's no magic here. You can definitely fade it, and make the rest of the floor cleaner, but that soda and wine is generally there to stay.
At best you can use some crazy spot treatment that lightens the area so much it doesn't match anymore, which still looks like a stain against the rest of the carpet.
I pity the carpet cleaners, I'd be extremely hesitant to get into an industry where you have to disappoint customers on a routine basis, and that's the industry norm.
If anyone has any serious arguments or methods I should try, we can easily put it to the test and I'd really be thrilled to be proven wrong. But I clean my carpets low-end and they look totally high-end!