Instead, there wasn't anything there that people already knew about/wanted. Consequently, there was no reason for people to want the platform. (i.e. Why do I want to pay for this new thing?!?)
Personally, I found Quibi's advertising so annoying and pointless that I would likely never be interested in looking past it to see what the platform was all about.
On the other hand, if they had started pushing shows/creators as an anchor for the platform (with something like an "only on Quibi ..." branding say) it might have been more interesting. I.e. make the platform secondary to the content, convince people they want the content, and that gives them a reason to look at the platform in the first place.
Basically, the consumers don't care about the platform itself so much as they care about what it provides them.
I'm not sure if that ad was targeted at Americans, at British, or at Americans who watch British stuff, but I can't imagine how it would come across well at any of those target audiences.
Quibi is different in that they tried to make a bunch of new content from scratch, and no one cared. They weren't tapping into an already existing well of demand for specific content.