It is the top tier of humans in these fields that are making the significant breakthroughs. The top tier of breakthroughs are not being post on here (which are nowadays usually short form articles of not incredible quality). The code at start ups is not commonly in the top tier of a breakthrough. AI can do averaged work and derivations off what has gone before which Maths works very well for as there is a clear set of rules. The same in physics if you ask AI for help adapting a simulation, yet it couldn't pluck the idea if no one has done it before.