Is it? There are a number of approaches that they can take that does not include installing trials. One is to ignore it altogether, another is to create links to the anti-virus vendor's website. I'm also guessing that many of the vendors of free anti-virus suites would be happy to license a non-trial version. In the last two cases, the vendors would probably be willing to pay a commission since it is still marketing for their products.

Is is? As you said, it's not too surprising. Yet look at the products that people buy, and you'll find that it has "annoying and invasive adware". Look at Kindles. Look at Kobos. Look at Android and iOS devices. All of these products track the consumer's behaviour to some degree. All of these products have storefronts, which are little more than advertising platforms. While there is certainly a huge difference between what these vendors are doing and what Superfish was doing because Superfish compromises upon security protocols, a lot of what it is doing is the norm these days.