I don't think he's worried about the legality of it all, or even compensation... it's more the fact of someone trying to get the kudos for the creativity and correct combination of the elements that built it. There's probably some creative director in their offices who feels like king shit right now. They all pat him on the back on the way in to the office in the mornings for his awesome bumblebee 2013 concept.
It wouldn't really matter if it was something that was more of an 'inspired by' type of thing, this looked like it took work to blatantly do. It's not a few parts here and there, it's like the exact same build and build style, which is something someone created from the bottom up.
Not only did they have to analyze exactly the same shit, they'd have to source it- for that of course it took research. During that research I'm sure they found him and how to reach him, but didn't want to give props for a badass design, but thought it was nice enough to use in their multi-million $ movie.