For obvious reasons the niche is a bit nebulous, but we can perhaps get a sense of it by feeling around the edges and looking at what sorts of things happened at Bell Labs and Xerox PARC that don’t seem to be happening now. While corporate labs (Including Bell Labs and PARC themselves) still exist, Corporate labs no longer fill the niche they did in the early-mid twentieth century.
The trick is to try to distinguish the “what” from the “how.” The What is the immutable characteristics of the activities that we want to try to recreate while The How is the particular set of tactics and strategies Bell Labs used to achieve The What. It’s important to distinguish between the two because we might need to use different tactics to achieve the same things in a new context. If you just blindly followed everything it would be ineffective and Cargo cult-y.
The other caveat is that there are exceptions to all of these. Startups and academic groups exist that embody these characteristics and not all golden age corporate labs did all these things all the time.
What were the characteristics of this niche?
I suspect that there is strong overlap between this niche and We have no flying cars - failures of paradigm-shifting engineering.