A. 12 years old is relatively new for tech / computer science. There aren't that many novel / widely adopted computer science ideas introduced each year.

B. This "merge" in particular utilizes innovations in computer science that were non-existent 12 years ago when the original Bitcoin whitepaper was published.

C. There continues to be loads of cutting edge CS research that is broadly applicable to the entire industry but is being spear-headed by blockchain development, for example work on Zero-Knowledge Proofs.