I think more recent languages also provide abstractions that reduce the frequency of off-by-one errors. Type systems also seem to have improved.

Unfortunately, even having tools that eliminate simple errors (like spell checkers and grammar checkers in ordinary writing) does not remove reasoning errors or clarity/conciseness issues.

(Efficient resource use is another dimension besides correctness and maintainability. Using an O(NlogN) method versus O(N×N) may be a mistake when N is small, but tools may lack the domain or profiling knowledge to detect such a mistake. Programming languages also seem to generally lack a way to express the importance of tail resource use, so even with profile information a tool might optimize for mean resource use.)

I think more recent languages have also attempted to increase clarity and conciseness by abstraction and consistent syntax. A newer language may also have more idiom consistency (some of the natural idiom divergence may be less more recently with easier communication -- the Internet functioning like cheap books did for spelling?).

I am not a programmer, but I do like thinking about such things.