There has been big progress in automated theorem proving lately
https://en.wikipedia.org/wiki/Automated_theorem_proving
you just don't hear about it much because the technology is not so fashionable today. Also it is more clear what the limits are, I mean, Turing, Godel, Tarski and all of those apply to neural networks as well any other formal system but people mostly forget it.
Knuth wrote a really fun volume of The Art of Computer Programming about advances in SAT solvers which are the foundation for theorem provers
https://www.amazon.com/Art-Computer-Programming-Fascicle-Sat...
Everybody is aware that neural network techniques have improved drastically in performance, it's much more obscure that the toolbox of symbolic A.I. has improved greatly. Back in the 1980s production rules engines struggled to handle 10,000 rules, now Drools can handle 1,000,000+ rules with no problems.