The black box isn’t being done because it’s a new idea, it’s actually the other way around. The newer idea is actually the method for easier analysis. There’s a few reasons that they aren’t doing that though.
It’s a newer idea, not everything has been studied so methods will be experimental.
It’s in the company’s interest to make the AI harder to analyze, because they don’t want open the door on a better algorithm from a different company/government/group.
It’s cheaper up front to build a black box and then do statistical analysis the hard and expensive way. Companies would much rather spend money doing things the wrong way instead of saving money long term doing things the right way.