Weight, its all about the weight!
I've worked on a bid for a current F1 team for factory and track solution. We lost out partially as they wanted the kit for free, or near enough with random kick backs and corporate deals. Honestly it was basically selling IT to a marketing team with the solution being the secondary concern.
The second reason we lost out was weight. Turns out adding only a few U of extra hardware adds quite a lot of cost in shipping weight over the whole season. It was crazy money for even an extra 30-50KG of kit. Our solution had some options no one else's did but as such weighed more.
The design was simple enough. 6 Node solution in the garage and a backup 4 node solution in the engineers truck.
Regardless of the outcome I loved working with them. Would still love to work in F1 but Its a young mans game these days and It'd be bloody hard to be away from home for such long periods through the year.