Sure but there is such thing as the "base topics" which, by specialising, we do get further from. Most people aren't working on fundamentals of quantum mechanic

Sure but there is such thing as the "base topics" which, by specialising, we do get further from. Most people aren't working on fundamentals of quantum mechanics for example. A lot of the problem is that in modern research you need to say your plan _before_ you get funding, and putting a new researcher into a field without a clearly defined project for them is considered a death sentence for any career possibility for them. Because of that reason, fields where the research has stopped progressing effectively stagnate for very long periods. No one will work on something unless there is a guarantee that high quality, impactful papers can be produced that will propel into a career