I think when looking at least at large scale applications in the context of games (and not just super-expensive showcases), like in the Stockfish chess engine, we see that it's not primarily about depth, it's about architecture design. Reference: start here https://stockfishchess.org/blog/2021/stockfish-14/ and go down the rabbit hole...
In the broadly useful domain of recommender systems (which typically make use of some type of RL-like feedback loop, but can be implemented using simple clustering approaches), at least in 2019, neural network-based approaches didn't seem to fair too well, either: https://arxiv.org/pdf/1907.06902.pdf (arXiv pre-print, but this is an award-winning paper).
Since then, it seems that researchers are moving away from getting deeper and deeper (the low-hanging fruit), and try to be more creative instead: new architectures, combining symbolic (logic-based) and sub-symbolic (ML-based) AI, etc.
In the broadly useful domain of recommender systems (which typically make use of some type of RL-like feedback loop, but can be implemented using simple clustering approaches), at least in 2019, neural network-based approaches didn't seem to fair too well, either: https://arxiv.org/pdf/1907.06902.pdf (arXiv pre-print, but this is an award-winning paper).
Since then, it seems that researchers are moving away from getting deeper and deeper (the low-hanging fruit), and try to be more creative instead: new architectures, combining symbolic (logic-based) and sub-symbolic (ML-based) AI, etc.