Over the last centuries there were a number of truck and bus manufacturers who tried the single/middle seat design. It was never a seller for any of those.

If you take someone with you, you don't want to sit him/her to sit behind you. You want them to sit next to you. If you are on the road in the city, you have often colleagues with you, like in a moving company and alike. Such trucks are used in construction work where things damage easily because someone else crashes in your truck. No assistant in your truck will prevent that.

Honestly, it seems they may have talked to some friends or their delivery companies, but not with companies from the industry.