It is also common meme that all new cars look the same

https://medium.com/swlh/the-zombie-mobile-b03932ac971d

This is just a signal that the field is mature and the design is near local optimum.

tbh I don't see that much exotic designs in military aircraft either. Something like Rafale, Eurofighter, Gripen, J-10 etc are all notably similar in design (pure delta with canards). Similarly, the new gen fighters also are quite similar to each other visually. X-32 was maybe the only outlier on top of my head, and it never left the prototype stage.