Definitely do not create three different pages for this type of content. The content is far too similar, mostly synonyms that lead to the same answer. Best case scenario, search engines will ignore some or (even less ideal) all of these pages; worst case, your whole site gets penalized for duplicate content and for trying to engage in keyword stuffing.
Search engines today know the synonyms and intent for most words, and search traffic tends to reflect this. Did you get website hits for all three phrases? If yes, it means Google figured out that your product is one of the best results for all of them, and your pages were displayed to users searching for this info. That the last one got the most searches means that's the one to optimize for. But Google knows that a truck is a vehicle, and a small truck is still a truck and a small vehicle.
My advice would be to put this all on one page, but get a little creative with the copy. By "creative," I mean make it sound natural, rather than trying to stuff every phrase variation into the page copy.
So something like: "Truck A is the best small truck for builders who need a vehicle for smaller jobs."
Not: "Truck A is the best small truck. Buy Truck A to get the best vehicle for builders. Because Truck A is the best truck if you're a builder."
That said, remember that this content phrasing is still an experiment. Set your KPI's (from which search phrase do you get the most hits and conversions?) and when you make changes, track your KPI's, so you can make adjustments in the future (or reversals if the trend is heading in the wrong direction).