The big one on the list that wasn't AT&T was microwaves and that was a contractor to Nasa [0] in the heat of the moon race and a similar "Do stuff. Then we'll see if we can use it" mandate.
[0] Defense contractor Raytheon most specifically.
I think that's one thing people truly forget when they ask "Why can't we do things like this anymore?"
AT&T paid people to fuck around. Claude Shannon, father of Information Theory, founder of Artificial Intelligence, and namesake to Anthropic's flagship product, was also busy building flame-throwing trumpets and rocket frisbees while creating entire new fields.
[0] Defense contractor Raytheon most specifically.