On the flip side, would product owners want to pay prospects to hear their pitch and try out their product?
I only do that if I look for a solution or the topic is of interest to me and tech/management magazines allow for a good preselection.
You need to remind yourself that techies and managers often earn good money, so more of it doesn't necessarily get them to listen. On the flip side there might be customers that only listen for the money without intend to buy anything.
I have no idea if presenters pay magazines, but I would assume they do. I like the honesty in those presentations where the presenters state what their product can and cannot do and perhaps give an outlook to what it planned in the future.
You often find quite good tools that aren't really known to a large audience but that can make life much easier for your company. It is also difficult to find them outside of such presentations through a web search.